Secret plans for a nuclear submarine found in a suitcase donated to a charity shop have been sold in an auction.

Bids for the cutaway plans of the £200 million HMS Trafalgar were received from as far away as America when they were put up for auction at Barnardo's Cymru's Porthmadog shop in North Wales.

Barnardo's said the plans will be making their permanent home with Mark Rice, who joined the Royal Navy when he was 16 and has spent 26 years as a submariner.

They were bought for him as a surprise present by his partner Tara Burke, who rang the Porthmadog shop every day during the five-day auction.

She managed to place the winning bid of £320 with just one minute to spare - by dashing into motorway services to make the call.

Mr Rice said: "I spent a lot of my life away under water in Trafalgar and have a lot of fond memories. Now I just need to get it framed and find a wall big enough to put it as it's six feet long."

Stella Parker, the Porthmadog shop manager who discovered the plans, said: "We have been overwhelmed by the interest.

"We even had an author of spy fiction from Colorado bid for it but we couldn't be more delighted that Tara has won it, it's a lovely story with a happy ending."