Mr Sperry had only been in Iraq for four weeks

Adam Sperry, 22, from Wigston near Leicester, is among the 15 Royal Navy personnel captured by the Iranians on 23 March.

Mr Sperry's brother James told BBC Radio Leicester his brother was "strong-minded" and would cope well.

The family added he had been in Iraq for four weeks before the capture and had joined the navy three years ago.

'Disgust with Iran'

Mr Sperry had been based in Faslane, Scotland, before leaving for Iraq.

Iranian authorities claim Mr Sperry was among the group that entered their territory and showed him - along with two other crew members Nathan Summers and Leading Seaman Faye Turney - on television on Friday.

James Sperry said he was looking forward to his older brother coming home. "Everyone's really worried about him but I'm confident he's all right, especially having seen the video today.

"He's a strong-minded lad, I think he'll be ok."

Mr Sperry's mother Sandra said her son was "just doing his job" and asked the Iranian authorities to send him home safely.

Prime Minister Tony Blair condemned the "parading" of the British crew in this way and said it would only "enhance people's sense of disgust with Iran".

The UK denies the crew had trespassed into Iranian territory.