It’s a line that Boris Johnson might have scripted himself. “Ken’s too busy to go to Havering, but he’s been to India.”

The results of two focus groups carried out by Populus on behalf of The Times appear to vindicate the Conservatives’ decision to dispatch their candidate to the suburbs. Voters from outer boroughs are more willing to switch support from Mr Livingstone than those from the centre of the capital, the research suggests.

The first focus group, the results of which were published on Wednesday, indicated that although the Johnson campaign had successfully delivered its messages to inner London voters they may lean towards Mr Livingstone after considering the choice in earnest.

With the race about to enter its final week, the latest evidence suggests that Mr Johnson could be in line for a last-minute surge in the outer boroughs. Of nine participants drawn from a cross-section of the capital’s suburbs, four said initially that they were supporting the Conservative candidate, two were leaning towards Mr Livingstone, one was Green and two were undecided. After ninety minutes of questioning and discussion, Mr Johnson had six likely voters – including one switching from Mr Livingstone. The Labour candidate picked up one undecided so remained on two, while the Green voter stuck to his cause.

From almost its start the Johnson campaign has been predicated on the proposition that there are, in effect, two electorates in the London mayoral election. Its aim has been to exploit the mismatch between the capital that the tourists see and the less glamorous reality endured by most residents.

The resonance of that message is clear within minutes of the start of the second group. Less clearly identified as Londoners, the group is more concerned about crime and litter than the inner Londoners and much less concerned about London’s reputation abroad or as a cultural centre.

One, a former Livingstone voter, said that the incumbent showed a “lack of respect”. Another that “he’s split people, giving with one hand and taking with another”, while a third complained that he had “become carried away with his own importance”.

Although Mr Johnson was initially judged “simplistic”, “eccentric” and a “likeable buffoon”, the suburban focus group was universally impressed with the Conservative’s party election broadcast. Shown all three main candidate’s campaign films, group members preferred Mr Johnson’s “specific” pledges. Brian Paddick, the Liberal Democrat candidate, succeeded in alienating the only person who was considering voting for him with his broadcast, and Mr Livingstone’s effort reminded the group of how long they had heard the same messages.

There were some intriguing similarities as well as the differences between the two groups. Asked to visualise Mr Livingstone coming into a pub, both imagined him in a suit, ordering a beer and not talking to anyone. Mr Johnson on the other hand would be colour-fully dressed, order a gin and tonic and talk freely to all, both agreed.

The second group confirmed the futility of any last-minute attempt by Labour to throw a question mark over Mr Johnson’s ability to handle a disaster. On the other hand it also underlined that attempts by the Conservatives to exploit Gordon Brown’s unpopularity in the mayoral race are largely pointless.

Andrew Cooper, the co-founder of Populus, said that although Livingstone’s message had greater resonance in inner London there was “a sense of overfamiliarity, even boredom, with him”.

He added: “Johnson seems largely to have succeeded in projecting a sufficiently serious, policy-centred message, to neutralise the potentially fatal ‘clown’ effect and the focus groups tend to suggest that he is viewed as more approachable than Livingstone, who in turn is felt to have become arrogant. For most voters there is little to choose between the candidates and not much at stake if one wins rather than the other.

“Unless one of the candidates can raise the stakes in the final few days, the winner is likely to be whichever campaign does the better job of getting supporters to turn out and vote.”

One purpose of focus groups is to draw out issues that may turn the outcome of a poll. One such subject might be allegations of racism and anti-Semitism.

Boris Johnson has apologised for using the word “piccaninnies” while Ken Livingstone having likened a Jewish reporter to a “concentration camp guard” is not forgotten.

The issue surfaced in the session with the outer London group. “All the people I know will never vote for him because of those comments,” said the only black member of the group about Mr Johnson. “Livingstone has been racist against Jewish people,” countered a white former Livingstone voter who has switched to the Tory. The subject was not pursued by the group, but was clearly going to motivate the way at least one intended to vote.

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