Inside the Commons2015

[as Father of The House, Sir Peter Tapsell is the only MP who does not need to reserve a back-bench seat in the House of Commons, but despite this, he always does so]

Sir Peter Tapsell:
The reason I put in a card is because I don't want the embarrassment of turning somebody out of their seat who may not know the convention in a crowded house, especially if it was a lady, which is quite a difficult thing to do. And the problem would arrise: do I sit on *her* knee or does she sit on *mine*.