Six days earlier we had landed at Faro airport. The coach was full of people like us, parents lugging multiple toddler/baby combinations. All of us had risen at dawn, rushed along motorways and hurtled across the sky in search of the modern solution to our exhaustion - the Mark Warner kiddie club. I travelled with my partner Jes, our three-year-old daughter, and our nine-month-old baby son. Praia da Luz was the nearest Mark Warner beach resort and this was the cheapest week of the year - a bargain bucket trip, for a brief lie-down.

Excitedly, we were shown to our apartments. Ours was on the fourth floor, overlooking a family and toddler pool, opposite a restaurant and bar called the Tapas. I worried about the height of the balcony. Should we ask for one on the ground floor? Was I a paranoid parent? Should I make a fuss, or just enjoy the view?

We could see the beach and a big blue sky. We went outside to explore.

We settled in over the following days. There was a warm camaraderie among the parents, a shared happy weariness and deadpan banter. Our children made friends in the kiddie club and at the drop-off, we would joke about the fact that there were 10 blonde three-year-old girls in the group. They were bound to boss around the two boys.

The children went sailing and swimming, played tennis and learned a dance routine for the end-of-week show. Each morning, our daughter ran ahead of us to get to the kiddie club. She was having a wonderful time. Jes signed up for tennis lessons. I read a book. He made friends. I read another book.

The Mark Warner nannies brought the children to the Tapas restaurant to have tea at the end of each day. It was a friendly gathering. The parents would stand and chat by the pool. We talked about the children, about what we did at home. We were hopeful about a change in the weather. We eyed our children as they played. We didn't see anyone watching.

Some of the parents were in a larger group. Most of them worked for the NHS and had met many years before in Leicestershire. Now they lived in different parts of the UK, and this holiday was their opportunity to catch up, to introduce their children, to reunite. They booked a large table every night in the Tapas. We called them "the Doctors". Sometimes we would sit out on our balcony and their laughter would float up around us. One man was the joker. He had a loud Glaswegian accent. He was Gerry McCann. He played tennis with Jes.

One morning, I saw Gerry and his wife Kate on their balcony, chatting to their friends on the path below. Privately I was glad we didn't get their apartment. It was on a corner by the road and people could see in. They were exposed.

In the evenings, babysitting at the resort was a dilemma. "Sit-in" babysitters were available but were expensive and in demand, and Mark Warner blurb advised us to book well in advance. The other option was the babysitting service at the kiddie club, which was a 10-minute walk from the apartment. The children would watch a cartoon together and then be put to bed. You would then wake them, carry them back and put them to bed again in the apartment. After taking our children to dinner a couple of times, we decided on the Wednesday night to try the service at the club.

We had booked a table for two at Tapas and were placed next to the Doctors' regular table. One by one, they started to arrive. The men came first. Gerry McCann started chatting across to Jes about tennis. Gerry was outgoing, a wisecracker, but considerate and kind, and he invited us to join them. We discussed the children. He told us they were leaving theirs sleeping in the apartments. While they chatted on, I ruminated on the pros and cons of this. I admired them, in a way, for not being paranoid parents, but I decided that our apartment was too far off even to contemplate it. Our baby was too young and I would worry about them waking up.

My phone rang as our food arrived; our baby had woken up. I walked the round trip to collect him from the kiddie club, then back to the restaurant. He kept crying and eventually we left our meal unfinished and walked back again to the club to fetch our sleeping daughter. Jes carried her home in a blanket. The next night we stayed in. It was Thursday, May 3.

Earlier that day there had been tennis lessons for the children, with some of the parents watching proudly as their girls ran across the court chasing tennis balls. They took photos. Madeleine must have been there, but I couldn't distinguish her from the others. They all looked the same - all blonde, all pink and pretty.

Jes and Gerry were playing on the next court. Afterwards, we sat by the pool and Gerry and Kate talked enthusiastically to the tennis coach about the following day's tournament. We watched them idly - they had a lot of time for people, they listened. Then Gerry stood up and began showing Kate his new tennis stroke. She looked at him and smiled. "You wouldn't be interested if I talked about my tennis like that," Jes said to me. We watched them some more. Kate was calm, still, quietly beautiful; Gerry was confident, proud, silly, strong. She watched his boyish demonstration with great seriousness and patience. That was the last time I saw them that day. Jes saw Gerry that night.

Our baby would not sleep and at about 8.30pm, Jes took him out for a walk in the buggy to settle him. Gerry was on his way back from checking on his children and the two men stopped to have a chat. They talked about daughters, fathers, families. Gerry was relaxed and friendly. They discussed the babysitting dilemmas at the resort and Gerry said that he and Kate would have stayed in too, if they had not been on holiday in a group. Jes returned to our apartment just before 9.30pm. We ate, drank wine, watched a DVD and then went to bed. On the ground floor, a completely catastrophic event was taking place. On the fourth floor of the next block, we were completely oblivious.

At 1am there was a frantic banging on our door. Jes got up to answer. I stayed listening in the dark. I knew it was bad; it could only be bad. I heard male mumbling, then Jes's voice. "You're joking?" he said. It wasn't the words, it was the tone that made me flinch. He came back in to the room. "Gerry's daughter's been abducted," he said. "She ..." I jumped up and went to check our children. They were there. We sat down. We got up again. Weirdly, I did the washing-up. We wondered what to do. Jes had asked if they needed help searching and was told there was nothing he could do; she had been missing for three hours. Jes felt he should go anyway, but I wanted him to stay with us. I was a coward, afraid to be alone with the children - and afraid to be alone with my thoughts.

I once worked as a producer in the BBC crime unit. I directed many reconstructions and spent my second pregnancy producing new investigations for Crimewatch. Detectives would call me daily, detailing their cases, and some stories stay with me still, such as the ones about a girl being snatched from her bath, or her bike, or her garden and then held in the passenger seat, or stuffed in the boot. There was always a vehicle, and the first few hours were crucial to the outcome. Afterwards, they would be dumped naked in an alley, or at a petrol station with a £10 note to "get a cab back to Mummy". They would be found within an hour or two. Sometimes.

From the balcony we could see some figures scratching at the immense darkness with tiny torch lights. Police cars arrived and we thought that they would take control. We lay on the bed but we could not sleep.

The next morning, we made our way to breakfast and met one of the Doctors, the one who had come round in the night. His young daughter looked up at us from her pushchair. There was no news. They had called Sky television - they didn't know what else to do. He turned away and I could see he was going to weep.

People were crying in the restaurant. Mark Warner had handed out letters informing them what had happened in the night, and we all wondered what to do. Mid-sentence, we would drift in to the middle distance. Tears would brim up and recede.

Our daughter asked us about the kiddie club that day. She had been looking forward to their dance show that afternoon. Jes and I looked at each other. My first instinct was that we should not be parted from our children. Of course we shouldn't; we should strap them to us and not let them out of our sight, ever again. But then we thought: how are we going to explain this to our daughter? Or how, if we spent the day in the village, would we avoid repeatedly discussing what had happened in front of her as we met people on the streets? What does a good parent do? Keep the children close or take a deep breath and let them go a little, pretend this was the same as any other day?

We walked towards the kiddie club. No one else was there. We felt awful, such terrible parents for even considering the idea. Then we saw, waiting inside, some of the Mark Warner nannies. They had been up most of the night but had still turned up to work that day. They were intelligent, thoughtful young women and we liked and trusted them. The dance show was cancelled, but they wanted to put on a normal day for the children. Our daughter ran inside and started painting. Then, behind us, another set of parents arrived looking equally washed out. Then another, and another. We decided, in the end, to leave them for two hours. We put their bags on the pegs and saw the one labelled "Madeleine". Heads bent, we walked away, into the guilty glare of the morning sun.

Locals and holidaymakers had started circulating photocopied pictures of Madeleine, while others continued searching the beaches and village apartments. People were talking about what had happened or sat silently, staring blankly. We didn't see any police.

Later, there was a knock on our apartment door and we let the two men in. One was a uniformed Portuguese policeman, the other his translator. The translator had a squint and sweated slightly. He was breathless, perhaps a little excited. We later found out he was Robert Murat. He reminded me of a boy in my class at school who was bullied.

Through Murat we answered a few questions and gave our details, which the policeman wrote down on the back of a bit of paper. No notebook. Then he pointed to the photocopied picture of Madeleine on the table. "Is this your daughter?" he asked. "Er, no," we said. "That's the girl you are meant to be searching for." My heart sank for the McCanns.

As the day drew on, the media and more police arrived and we watched from our balcony as reporters practised their pieces to camera outside the McCanns' apartment. We then went back inside and watched them on the news.

We had to duck under the police tape with the pushchair to buy a pint of milk. We would roll past sniffer dogs, local police, then national police, local journalists, and then international journalists, TV reporters and satellite vans. A hundred pairs of eyes and a dozen cameras silently swivelled as we turned down the bend. We pretended, for the children's sake, that this was nothing unusual. Later on, our daughter saw herself with Daddy on TV. That afternoon we sat by the members-only pool, watching the helicopters watching us. We didn't know what else to do.

Saturday came, our last day. While we waited for the airport coach to pick us up, we gathered round the toddler pool by Tapas, making small talk in front of the children. I watched my baby son and daughter closely, shamefully grateful that I could.

We had not seen the McCanns since Thursday, when suddenly they appeared by the pool. The surreal limbo of the past two days suddenly snapped back into painful, awful realtime. It was a shock: the physical transformation of these two human beings was sickening - I felt it as a physical blow. Kate's back and shoulders, her hands, her mouth had reshaped themselves in to the angular manifestation of a silent scream. I thought I might cry and turned so that she wouldn't see. Gerry was upright, his lips now drawn into a thin, impenetrable line. Some people, including Jes, tried to offer comfort. Some gave them hugs. Some stared at their feet, words eluding them. We all wondered what to do. That was the last time we saw Gerry and Kate.

The rest of us left Praia da Luz together, an isolated Mark Warner group. The coach, the airport, the plane passed quietly. There were no other passengers except us. We arrived at Gatwick in the small hours of an early May morning. No jokes, no banter, just goodbye. Though we did not know it then, those few days in May were going to dominate the rest of our year.

"Did you have a good trip?" asked the cabbie at Gatwick, instantly underlining the conversational dilemma that would occupy the first few weeks: Do we say "Yes, thanks" and move swiftly on? Or divulge the "yes-but-no-but" truth of our "Maddy" experience? Everybody talks about holidays, they make good conversational currency at work, at the hairdresser's, in the playground. Everybody asked about ours. I would pause and take a breath, deciding whether there was enough time for what was to follow. People were genuinely horrified by what had happened to Madeleine and even by what we had been through (though we thought ourselves fortunate). Their humanity was a balm and a comfort to us; we needed to talk about it, chew it over and share it out, to make it a little easier to swallow.

The British police came round shortly after our return. Jes was pleased to give them a statement. The Portuguese police had never asked.

As the summer months rolled by, we thought the story would slowly and sadly ebb away, but instead it flourished and multiplied, and it became almost impossible to talk about any-thing else. Friends came for dinner and we would actively try to steer the conversation on to a different subject, always to return to Madeleine. Others solicited our thoughts by text message after any major twist or turn in the case. Acquaintances discussed us in the context of Madeleine, calling in the middle of their debates to clarify details.

I found some immunity in a strange, guilty happiness. We had returned unscathed to our humdrum family routine, my life was wonderful, my world was safe, I was lucky, I was blessed. The colours in the park were acute and hyper-real and the sun warmed my face.

At the end of June, the first cloud appeared. A Portuguese journalist called Jes's mobile (he had left his number with the Portuguese police). The journalist, who was writing for a magazine called Sol, called Jes incessantly. We both work in television and cannot claim to be green about the media, but this was a new experience. Jes learned this the hard way. Torn between politeness and wanting to get the journalist off the line without actually saying anything, he had to put the phone down, but he had already said too much. Her article pitched the recollections of "Jeremy Wilkins, television producer" against those of the "Tapas Nine", the group of friends, including the McCanns, whom we had nicknamed the Doctors. The piece was published at the end of June. Throughout July, Sol's testimony meant Jes became incorporated into all the Madeleine chronologies. More clouds began to gather - this time above our house.

In August, the doorbell rang. The man was from the Daily Mail. He asked if Jes was in (he wasn't). After he left I spent an anxious evening analysing what I had said, weighing up the possible consequences. The Sol article had brought the Daily Mail; what would happen next? Two days later, the Mail came for Jes again. This time they had computer printout pictures of a bald, heavy-set man seen lurking in some Praia da Luz holiday snaps. The chatroom implication was that the man was Madeleine's abductor. There was talk on the web, the reporter insinuated, that this man might be Jes. I laughed at the ridiculousness of it all and then realised he was serious. I looked at the pictures, and it wasn't Jes.

Once, Jes's father looked him up on the internet and found that "Jeremy Wilkins, television producer" was referenced on Google more than 70,000 times. There was talk that he was a "lookout" for Gerry and Kate; there was talk that Jes was orchestrating a reality-TV hoax and Madeleine's disappearance was part of the con; there was talk that the Tapas Nine were all swingers. There was a lot of talk.

In early September, Kate and Gerry became official suspects. Their warm tide of support turned decidedly cool. Had they cruelly conned us all? The public needed to know, and who had seen Gerry at around 9pm on the fateful night? Jes.

Tonight with Trevor McDonald, GMTV, the Sun, the News of the World, the Sunday Mirror, the Daily Express, the Evening Standard and the Independent on Sunday began calling. Jes's office stopped putting through calls from people asking to speak to "Jeremy" (only his grandmother calls him that). Some emails told him that he would be "better off" if he spoke to them or he would "regret it" if he didn't, implying that it was in his interest to defend himself - they didn't say what from.

Quietly, we began to worry that Jes might be next in line for some imagined blame or accusation. On a Saturday night in September, he received a call: we were on the front page of the News of the World. They had surreptitiously taken photographs of us, outside the house. There were no more details. We went to bed, but we could not sleep. "Maddie: the secret witness," said the headline, "TV boss holds vital clue to the mystery." Unfortunately, Jes does not hold any such vital clues. In November, he inched through the events of that May night with Leicestershire detectives, but he saw nothing suspicious, nothing that would further the investigation.

Throughout all this, I have always believed that Gerry and Kate McCann are innocent. When they were made suspects, when they were booed at, when one woman told me she was "glad" they had "done it" because it meant that her child was safe, I began to write this article - because I was there, and I believe that woman is wrong. There were no drug-fuelled "swingers" on our holiday; instead, there was a bunch of ordinary parents wearing Berghaus and worrying about sleep patterns. Secure in our banality, none of us imagined we were being watched. One group made a disastrous decision; Madeleine was vulnerable and was chosen. But in the face of such desperate audacity, it could have been any one of us.

And when I stroke my daughter's hair, or feel her butterfly lips on my cheek, I do so in the knowledge of what might have been. But our experience is nothing, an irrelevance, next to the McCanns' unimaginable grief. Their lives will always be touched by this darkness, while the true culprit may never be brought to light.

So my heart goes out to them, Gerry and Kate, the couple we remember from our Portuguese holiday. They had a beautiful daughter, Madeleine, who played and danced with ours at the kiddie club. That's who we remember.

© Bridget O'Donnell 2007.

· Bridget O'Donnell is a writer and director. The fee from this article will be donated to the Find Madeleine fund (findmadeleine.com).