Archer, who was released from prison in July after serving two years of a four-year sentence for perjury, reportedly plans to raise £1 for every inch of the 26 mile and 238 yard course, bringing in a total of more than £1.66m.
The disgraced peer has approached four charities, including the British Heart Foundation, to discuss how they could benefit from the venture.
"We met with Archer this week for an exploratory discussion," said David Barker, head of communications at the British Heart Foundation. "No final decisions have been made, but we talked about how we could move things forward."
The charity has already courted controversy by working with disgraced ex-MP Neil Hamilton and his wife Christine. The pair were photographed in a bath of strawberry jam to promote the charity's Heart Week fundraising campaign.
To clinch the new world record, Archer will have to beat the current record holder American rap star P Diddy, who raised £1.19m at this year's New York Marathon.
He will be also be vying to beat the efforts of the Prime Minister's former press secretary Alistair Campbell, who raised £320,000 for the Leukaemia Research Fund by running the 2003 London Marathon (Third Sector, 3 September). Campbell hit the headlines with celebrity sponsors including Prime Minister Tony Blair and US President George Bush.
Archer is understood to have been training for three months, and is likely to beat the time of Lloyd Scott, who completed the 2002 London Marathon in five days and eight hours, dressed in a 120lbs antique diving suit.
Archer is to announce the names of the charities that will benefit from the race in the next few weeks.