Arithmetic suggests he will have to break his word on something.

ECONOMIST: So many challenges. So little spare cash

His claim that he did not break his word appears to rest on the argument that dealing in shares in someone else's name does not amount to dealing at all.

ECONOMIST: Lord Archer

In a party political broadcast filmed at his home the Liberal Democrat leader speaks directly to camera and with real intensity about a decision which he believes has become a weight around his and his party's ankles - the decision to break his word by first signing, then breaking a pledge to vote against increases in student tuition fees.

BBC: Nick Clegg: Sorry no longer the hardest word