A GROUP of politics students advised an MP in an unexpected debate on the train to London.

The Penistone Grammar sixth formers were travelling to the capital on Monday for a tour of Parliament with MP Angela Smith.

But the train had barely left Wakefield Westgate station when Colne Valley MP Jason McCartney joined them for an off-the-cuff debate, posting later on social network Twitter he had had a 'cracking chat' about gay marriage, votes at 16 and the death penalty.

"I heard one of them say 'the Tories are voting on gay marriage,'" he said. "I went up and introduced myself, they said who they were, and I ended up sitting with them for the whole journey.''

Jason also consulted the students on the effect Tesco has had on Penistone over the last two and a half years - as there may be one opening in Holmfirth, which is in his constituency.

Steven Loring, head of government and politics at Penistone Grammar, said it was a wonderful coincidence that was a useful experience for the students.

He said: "Because of the nature of the subject, you can't just do it out of a text book, so it was great they got the chance to debate with a sitting MP, as they're very articulate and able to hold their own.''