New equipment valued at £18m will be installed as part of a general overhaul of the ship under a £17m contract with Babcock Marine at their Rosyth dockyard in Scotland.

Baroness Taylor, Minister of State for Defence Equipment and Support, said:

"HMS Sutherland is the first of our ships to get this new equipment making her the most powerful frigate in the fleet. With an improved air defence missile system, a new long-range main gun, and our latest and most sophisticated submarine-hunting sonar, she will be a force to be reckoned with, capable of dealing with current and future threats."

The Type 23 frigate is to get:

• the Navy's latest and most sophisticated submarine hunting sonar system, capable of identifying submarines at an even greater range;
• an advanced Sea Wolf air defence missile system, which will counter the advanced threat from missiles and fixed wing aircraft;
• a new improved main gun, capable of firing long-range ammunition;
• a reshaped stern to cut fuel use.

HMS Sutherland will be one of the first ships in the fleet to benefit from the £300m upgrade of the Sea Wolf Missile defence system by BAE Systems Insyte, greatly enhancing her anti-aircraft capabilities.

The frigate's new submarine-hunting capacity will come as part of a £166m sonar project run by Thales UK:

Sonar Type 2087 is an active low-frequency sonar in which a towed float is trailed from the frigate's quarterdeck, providing the 'ping' sound; a much used feature of many submarine-hunting films. When the sound wave hits a submarine, the return 'echo' is picked up by a towed array, also trailed from the quarterdeck on a cable up to 2km long. The results are then fed back to the ship sonar operators' screens.