Boris Johnson says there is "absolutely no doubt" he will be elected Mayor of London - and step down as an Oxfordshire MP.

The Henley MP gave his confident prediction to parliamentary journalists, despite a recent poll showing him trailing behind sitting mayor Ken Livingstone ahead of the election on May 1.

The Tory MP later told the Oxford Mail that he would quit as MP if elected mayor, triggering a by-election if he left before the next General Election.