Mr Livingstone later offered an olive branch to Mr Johnson by closing an attack website aimed at the Mayor as he warned the election race was getting "out of hand". He said:
"Those of us who are leading candidates in this election have a duty to the electorate to rein it in and direct it to the issues at stake for Londoners.
"I suggest to Boris Johnson therefore that he and I work together to raise the tone and spirit of this election."
More top news
One newspaper has picked a northern city as Britain's best place to live, due to its ancient beauty and recent modernisation.
A shock to the system
We found a tableau of desperation; vast crowds of people pushing and shoving their way forward, away from the continuing bombardment.