University challenged: Trimble's team-mate wasn't a student

University Challenge's losing finalists have demanded a rematch, after it emerged that a member of Gail Trimble's victorious Corpus Christi side was no longer a student at the Oxford college.

Sam Kay, of Frimley in Surrey, seems to have breached the rules by claiming he was still studying chemistry, when in fact he had graduated with a first in June and was working for PricewaterhouseCoopers. Contestants are required to be students for the duration of the competition's filming and broadcasting.

In the final against Manchester University, recorded two months ago, Mr Kay correctly answered two starters-for-10 when Corpus Christi were lagging. More than 5.3 million people tuned in on Monday, after Ms Trimble's performances in earlier rounds led to her being dubbed "the greatest contestant ever".

Manchester contestant and PhD student Henry Pertinez, 27, said: "They must have made a mistake with the application. Granada was very strict. It's unfortunate, but all of us would definitely be up for a rematch."

Mr Kay told The Observer: "I was a student when I applied to be on the show and when we filmed the first two rounds, so I don't think I've done anything wrong." A BBC spokesman said the corporation was investigating and expected to announce its findings early next week.