HUNTER-killer submarine HMS Trenchant has been stalking the lochs of Scotland as she testing her proficiency with the torpedo.

The Devonport-based Trafalgar-class submarine headed to the BUTEC – British Underwater Test and Evaluation Centre – ranges at the Kyle of Lochalsh to fire a number of specially-modified ‘fish’.

Warheads were removed from Spearfish torpedoes – the standard wire-guided weapon used by Fleet submarines against surface and sub-surface targets – and replaced with ‘recording devices’ which gathered data from the torpedo’s run.

Trenchant fired a number of these modified torpedoes on the BUTEC range against a mixture of targets above and below the waves, demonstrating that both her crew and her weapons systems were fit for front-line duties.

The boat spent 2006 in Devonport undergoing an overhaul, but is making up for the time alongside in 2007 with strenuous activity.

She is currently being put through her paces by the team of the Flag Officer Sea Training in Faslane who oversee all operational training for Britain’s Silent Service.