General Election 2015 poll tracker: Who will win on 7 May?

It's one of the most nail-biting elections in history. City A.M.'s poll tracker measures the latest support for each of the six main parties - the Conservatives, Labour, the Liberal Democrats, Ukip and the Green Party.

We've taken data from eight researchers, YouGov, Populus, Survation, ComRes, ICM, TNS BMRB and Ipsos-MORI, all of whom are members of the British Polling Council, and Lord Ashcroft, who is not. In each case, the date listed is the final date of research.

The doughnut shows the average figure for each party, based on polls from the past two weeks.

2 week averages

Latest polls

Date Poll Con Lab Lib UKIP Grn

What the pollsters ask

Yougov: If there were a general election tomorrow, which party would you vote for? Conservative, Labour, Liberal Democrat, Scottish Nationalist/Plaid cymru, some other party, would not vote, don’t know

Populus: If the general election was tomorrow, which party would you vote for? Would it be [rotate order] Conservative, Labour, Liberal Democrat, or another party – or would you not vote at all?

Survation: Respondents are typically asked who they would be most likely to vote for if that election were tomorrow, with the responses 'Labour', 'Conservative', 'Liberal Democrat' and 'UKIP' prompted in a randomising order, and other parties listed if respondents select 'Another Party'.

ComRes: At the UK General Election coming up in May, when MPs are elected to Westminster, will you vote [rotate order] Liberal Democrat, Labour, Conservative or Ukip? (NB. In Scotland this includes SNP)

ICM: The Conservatives, Labour, the Liberal Democrats and other parties would fight a new election in your area. If there were a general election tomorrow which party do you think you would vote for?

Ipsos-MORI: How would you vote if there were a General Election tomorrow?

Lord Ashcroft: If there was a general election tomorrow, which party would you vote for?