Responding to the publication of a YouGov poll in the Evening Standard, a spokesperson for Ken Livingstone said:

"YouGov's internet polls on the London Mayor election are totally out of line with polls using established methods, like that of ICM last week which showed Livingstone and Johnson to be neck and neck, this is because You Gov's methodology is fundamentally flawed. In their previous London poll, for example, although the Office of National Statistics estimates 26% of Londoners to be aged 55-plus, You Gov's weighted data gave 39% in this age group, similarly You Gov do not take account of the much larger ethnic minority population in London. These and other mistakes mean that they consistently over-estimate support for the Conservatives in London compared to established polling techniques and, as last week, we clearly reject this poll. You Gov's polls are misleading the public and we have therefore decided to make a formal complaint about their basic flaws to the Market Research Council of Great Britain."