This is how Army reservists coped with one of their most challenging exercises in Portsmouth

Dozens of troops from B Company, third battalion, the Princess of Wales's Royal Regiment (3PWRR) took part in the mock exercise.

The 52 soldiers were tasked with launching an assault on a fictional enemy on board HMS Bristol at Whale Island.

Battling through the tight corridors of the obsolete Type 82 destroyer, the team was forced to fight through the lower decks, clearing cabins and eliminating enemies.

Then, after completing this, the company moved to Fort Widley for the second phase of the operation, which involved a night assault on the tunnels deep below the fort.

Using night vision and firing blank ammunition, the team battled into the early hours of the morning before eventually overwhelming their mock opponents.

The exercise was preparing the company, which is made up of reservists from Portsmouth and Sussex, for a major training exercise in the USA later this year.

Captain Gary Pullen, of Portsmouth, said: '˜It was an incredibly challenging exercise.'