Respondents said the other important factors are tackling crime (49 per cent), improving public transport (38 per cent) and building cheap homes (37 per cent).
The research, commissioned by the BBC, showed that both Boris Johnson and Ken Livingstone are tied on 27 per cent support when it came to public trust in their economic plans.
Livingstone’s policy of fare reductions is shown to be popular and he is thought to be in touch with the needs of ordinary Londoners.
But Johnson’s personal popularity was far ahead, with 43 per cent saying they liked the Conservative candidate the most, against 35 per cent who preferred Livingstone.
Turnout will be a crucial issue, with Johnson once again set to dominate the suburban vote.
London Elects – the body that runs the contest – yesterday published data that showed variations in turnout at the 2008 election.
While some east London wards saw fewer than 30 per cent of the electorate vote, suburbs such as Sutton hit 58 per cent turnout.