Last night's delays over whether to include Mr Livingstone on the mayoral shortlist have put on hold Downing Street's plans to attack his record, but the likely tone of the attacks became clear. Day one of the "Dirty War", as some Labour insiders have called it, was marked by the Tory party issuing a memo urging all its MPs to describe Mr Livingstone as "terrorist- friendly".
In a move that upstaged Millbank's attempts to assassinate his character, the bulletin from the Tory research department gives detailed advice on attacking the man who once led the Greater London Council.
The memo, titled The Line to Take - Red Ken, includes sections on "Livingstone the extremist" and attacks policies he has floated such as an airport tax and a pounds 7.50 congestion charge for motorists. "The election of Livingstone would mean an unwelcome return of the Loony Left, terrorist-friendly, tax-and-spend, socialist policies of the old GLC."
The advice from Conservative Central Office contrasts with the stance of its candidate, Lord Archer of Weston-super-Mare, who only last month ruled out using personalised negative campaigning.
Labour's attempts to erode support for the Brent East MP started even before the London selection board began its interviews yesterday with the four candidates hoping to become the party's choice for Britain's first directly elected mayor.
Lord McIntosh, who was ousted as leader of the GLC by Mr Livingstone in 1981, led the charge on BBC Radio's Today programme, accusing him of disloyalty to New Labour. Lord McIntosh also claimed the MP had been offered and turned down a ministerial job. The allegation was dismissed by the Livingstone camp as "pure fiction". Tony Blair, who has given public backing for Frank Dobson, was expected to lead the charge against Mr Livingstone in an article this week in the Evening Standard.
In a high-risk strategy that could backfire if the backbencher does win the contest, Mr Blair will portray the battle as one between Old and New Labour. The article is the first shot in a concerted Downing Street campaign, and will be followed by similar comments from Gordon Brown, the Chancellor, and most of the Cabinet over the next few weeks. Ministers will portray Mr Livingstone as the embodiment of the "Loony Left" years of the 1980s.
With most unions backing Mr Livingstone and MPs backing Mr Dobson, the party's electoral college will be decided by the members in the capital. It is estimated that Mr Livingstone needs to win the backing of at least 70 per cent of the membership to have a chance of winning.
Although the party is supposed to remain impartial in the contest, the full might of Labour's Millbank machine will be directed against the former GLC leader. Official rules prevent any candidate from "attacking or denigrating" their rivals, but the Dobson camp believes that this does not rule out clashes over their policies or record in government.
When Mr Dobson launches his manifesto tomorrow, it is expected that he will be supported by at least 20 ministers. But Mr Livingstone will do his best to counter what it calls the "propaganda" against him.