Four of the Royal Navy’s smallest ships are preparing to brave three weeks of rough seas as they head far north into the Arctic for Exercise Steadfast Defender, Nato’s largest exercise since the Cold War.

P2000 patrol boats HMS Biter, Blazer, Exploit and Trumpeter sailed from Portsmouth Naval Base at the start of their journey to Norway’s Arctic coast.

The fibreglass-hulled ships, which normally patrol coastlines, are just 20.8 metres long and have a displacement of 54 tonnes, with a crew of five on board.

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Lieutenant Cameron Osborne, the captain of HMS Exploit, told Forces News: “We will be port-stopping all the way up rather than one big journey as larger ships would do.

“Our first stop Ramsgate today, over to Holland, Germany, Denmark and then we’re up into the Norwegian fjords.

“Hopefully the weather will play less of an impact and we can get up right up to the Arctic Circle.”

During the deployment the Archer-class craft will have to cope with temperatures averaging minus 6C, dropping to around minus 30C in the High North when they sail above the 70th parallel.

They will be working closely with the Norwegian Coastal Commandos, Royal Marines and US Marine Corps.

Ltt Osborne said this was an exciting opportunity for them to push “the limits of what the Coastal Forces Squadron has done since World War Two”.

He added: “The squadron was derived then and we’ve moved away from that day sort of warfighting routes towards the university training.

“We’re now going back to our core role, which will be working in the Arctic Circle, delivering people and other sorts of operations as part of that exercise.”

For Able Seaman Nina Goodwin, who joined the Royal Navy just over a year ago, this will be her first deployment.

It is the first time she will be tested by rough seas, to which she said: “I think I’ve been out a couple of times on HMS Blazer in kind of rough weather and I’ve not been seasick.

“So I’m hoping that when we go today that will confirm I’m definitely not seasick.”

 After two weeks on Steadfast Defender, the vessels will then move on to a second Exercise Tamba Shield, training Royal Navy Wildcat helicopter crews in fast boat tactics.

HMS Queen Elizabeth, the fleet’s largest ship who had been due to lead Exercise Steadfast Defender, was forced to pull out last minute after final inspections spotted a problem with the starboard propeller coupling.

Now HMS Prince of Wales is being made ready to take the place of the £3bn fleet flagship.