The Tories are on 34% – down two percentage points since a week ago – while Labour is up one on 33%. Ukip, defying predictions that it would fade, is unchanged on 13% while the Liberal Democrats are up one point on 9%.
The Greens are also up one point on 6%, while the SNP is unchanged on 4%.
Although Labour is just behind, the fact that the Tory lead has fallen three points in the past week may encourage the party to believe the momentum is behind Ed Miliband rather than David Cameron as the final run approaches.
The fact that the two main parties are neck and neck suggests that a hung parliament is by far the most likely outcome on 8 May, with no single party winning an outright majority.
Labour will also be encouraged, however, that Miliband’s personal ratings have continued to improve, while Cameron’s have slipped, albeit from a high base.
The Labour leader has improved from a net rating of -18% a week ago to -13%, while Cameron’s score has fallen back from 0 to -4%.
The nine point advantage for the prime minister is one of the smallest recorded in recent months by Opinium.
Nigel Farage’s net rating is -18% while Nick Clegg’s is -31%, though this score is a marked improvement for the Lib Dem leader who ratings have plumbed far lower depths as he has battled to win back the public after five bruising years in coalition.
Opinium also asked voters a series of questions to test their views on the SNP, after a week in which the Conservatives have campaigned heavily on the theme that a Labour government propped up by Nicola Sturgeon’s anti-austerity party would be bad for the UK economy and would mean special favours for the Scots.
There was a prevailing view that the SNP could not be trusted to act in the best interests of the UK if it was part of the Westminster government. More than half – 56% – agreed with the statement that they could not be trusted while 16% disagreed.
However, twice as many voters (46%) believed it would be undemocratic to exclude the SNP from having a say in how the UK is governed – their MPs having been duly elected – as thought the reverse (23%).
When asked whether those politicians who play up the dangers of the SNP are putting the future of the union in doubt by alienating Scottish voters, 44% said they were putting the union in jeopardy while 21% said they were not.
About 49% said they believed that if Labour were dependent on the votes of the SNP to run a government, then Scotland would be better treated than the rest of the UK, while 17% disagreed.
Opinium Research carried out an online survey of 1,964 British adults aged 18+ from 21 to 24 April 2015. Results have been weighted to nationally representative criteria.
guardian.co.uk © Guardian News and Media Limited 2010