Next year's mayoral election will be a contest between the progressive left and the regressive right if Boris Johnson is selected as a candidate, a pressure group has claimed.
Compass, which campaigns for a democratic left, has taken the unusual step of publishing a dossier on Mr Johnson's rightwing past, aiming to dispel the idea of the Tory MP as a cycling buffoon.
Based on his past statements as an MP and journalist, Compass concludes Mr Johnson is the most rightwing candidate ever presented by a major party to stand as mayor of London.
Chuka Umunna a London political activist from the Compass Management Committee said: "With John Redwood and Boris Johnson the Tory party is now putting its most unacceptable face forward.
"John Redwood represents the hard faced character of the Tory right - with its willingness to risk even health and safety in pursuit of a right wing agenda.
"Boris Johnson represents the type of out-of-touch public school Toryism that thinks it's acceptable to refer to black people as 'picaninnies' and as having 'water melon smiles' - remarks for which he has been strongly attacked within the black community."
She claimed Compass' report shows the full extent of Mr Johnson's economic and social policies.
It notes the MP for Henley on Thames supported the election of George W Bush in 2000 and 2004, voted for the war in Iraq, opposed the Kyoto treaty, opposed the national minimum wage and pension rights for part-time workers and defended Section 28.
He has also warned against "too zealous" attempts to tackle inequality and said the inquiry into the killing of Stephen Lawrence was "Orwellian," Compass claimed.
Mr Johnson said the report was "a measure of the desperation of Ken and his cronies".
"They have gone through 20 years of articles in the hope of finding any phrase they can distort to the point of giving a completely false impression of what I believe."
Compass' report has not been universally welcomed, even by those people who oppose Mr Johnson's candidacy.
Ms Umunna defended the move, however, and argued it was "essential" Londoners knew the truth about Mr Johnson - who has a considerable fanbase thanks in part to his appearances on televisions shows such as Have I Got News For You.
Launching the report, Compass said: "Normally the internal mechanisations of the Tory Party would be of little interest to Compass but the nature of Johnson's politics and who, if he is successful, he will stand against make it an incredibly important election for the future of progressive politics".
Ken Livingstone has admitted Mr Livingstone is a "formidable" opponent.
Describing his likely opponent as a "charming and engaging rogue", the mayor said he would be "no walkover".
Mr Livingstone promised to focus his campaign on Mr Johnson's political beliefs rather than media image, claiming he was so rightwing "he makes Norman Tebbit look like a cuddly liberal".