A poll to be published the day before the European elections will suggest the battle for third place will be between the Green Party, the Liberal Democrats and UKIP.
In the new poll, conducted by ComRes (1), the Greens display their best ever Euro-election poll results.
If the poll proves accurate, the Greens will win a number of extra seats, as well as holding their current seats in London and the South East.
A ComRes poll in today's Independent newspaper puts the Green Party on 8% for a general election - the highest the Greens have ever polled in a survey about Westminster elections.
Consistent high polling
While opinion polls during the 2009 election campaign have produced varying results - for example, with UKIP oscillating between 7% and 19% - the Green Party has consistently polled well.
Last Sunday's Telegraph/ICM poll showed the Greens on 11%, ahead of UKIP nationally for the first time in the campaign. The Sunday Telegraph suggested that "the resurgent Greens" might win eight seats.
And in an earlier Green Party/YouGov poll, 34% of respondents said they would either definitely vote Green or consider voting Green if they knew more about the party.
Caroline Lucas, leader of the Green Party, said: "It's not all protest vote. I think our manifesto for a million jobs, aimed at tackling the recession and the climate crisis at the same time, has probably struck a chord with a lot of people."
Note
1. Commissioned by the Green Party. Fieldwork carried out 29-31 May 2009. Sample size 1,005 GB adults, polled by telephone.