The Chancellor is said by friends of Ms Jackson to see the double Oscar winner as the best candidate emerging to carry the Labour banner if the referendum for a directly elected mayor produces a "yes" vote on 7 May.
Ms Jackson, the transport minister for London, is also expected to have the tacit approval of John Prescott, her boss at the Department of Environment, Transport and the Regions, although as Deputy Prime Minister, he is not expected to endorse any candidate until one is agreed by the party.
"John would not stand in Glenda's way," said one source close to Mr Prescott.
Ms Jackson is expected to campaign on the inner cities, homelessness and reducing crime in London, once her campaign starts in earnest. With two years to go, there is a danger of peaking too soon. But Lord Archer's bandwagon to become the Tory candidate for London's mayor has been rolling for months.
Lord Archer said at the weekend that he had a campaign squad of six team leaders already in place with Greg Hutchins, a wealthy businessman, acting as his campaign treasurer and Stephen Shakespeare as a paid special adviser.
As a multi-millionaire, Lord Archer may take some stopping, even by Tory leaders who are still hoping to find a heavyweight, such as Chris Patten, the former Governor of Hong Kong, as a "stop Jeffrey" candidate.
Tory leaders fear that the irrepressible Lord Archer could embarrass the party. He said at the weekend: "I'm vulgar. I'm a populist. But isn't that what the mayor should be?"
The Tories are committed to holding an internal one-member, one-vote ballot to select a candidate but are threatening to boycott the "vote yes" campaign in the referendum, because they oppose an assembly for London.
Labour has yet to declare its preferred system for selecting its candidate, but it too is likely to opt for one-member one-vote for the primaries among Labour members in London.
Ms Jackson's campaign team is likely to be headed by her son, Dan Hodges, who is the spokesman for the road haulage association. The association's head, Steve Norris, a former Tory transport minister who held Ms Jackson's job, could be a strong Tory candidate, if he chose to stand against Lord Archer.
Ms Jackson is being careful to avoid making any public declaration, but a senior ministerial source said: "She is very keen to stand and she would have a lot of solid backing."
Amid intense jockeying for position, Trevor Phillips, the broadcaster, is being promoted as a possible candidate allegedly with the support of Peter Mandelson, the Minister Without Portfolio.
There is plenty of back-stabbing going on, even before the race has started, with one Cabinet source warning that other Labour runners would not stand down for Mr Phillips, if he stood as an independent candidate.
There is also a "stop Ken" campaign to block Ken Livingstone, former leader of the Greater London Council, from gaining Labour's candidacy in the primaries because he is too left wing.
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