Labour may have won enough support in the south west to overtake the Conservatives, according to an exclusive nationwide survey of voting intentions.

Of 750 people surveyed across the region, 34 per cent said they are planning to vote Labour later this week, compared to 25 per cent who said that was their planned vote at the start of the election campaign. The proportion of respondents backing the Tories is at 26 per cent, compared to 31 per cent backing the party at the start of the campaign.

A similar survey at the start of May found 39 per cent of respondents in the region said they were planning to vote Tory on June 8, compared to the 36 per cent who said they voted for the party in 2015, while the Labour vote was at 28 per cent, up from the 27 per cent who said they had voted for the party in 2015.

Other parties have seen their vote share squeezed by the contest between Labour and Conservatives - the UKIP vote was 3.3 per cent, compared to 4.3 per cent saying they supported the party at the start of the campaign, the Greens were 3.8 per cent, down from 4.7 per cent, although the Liberal Democrats have seen a small increase and were on 8.7 per cent, up from 8.6 per cent.

Three-quarters of people who planned to vote Conservative at the start of the campaign are still backing the party, but 10 per cent who were going to support the party have switched to Labour, and 9 per cent say they are no longer sure who they will vote for.

Labour on the other hand seem to be picking up support from all sides, while 92 per cent of those who planned to vote Labour at the start of the campaign are sticking with their party, 29 per cent of people who previously planned to vote Liberal Democrat said they have switched to Labour, as have 20 per cent of those who had been planning to vote Green, and 3 per cent of those previously backing UKIP. 

More than a quarter of respondents who said they were not sure what their vote would be at the start of the campaign are now behind Labour at 28 per cent, compared to 6 per cent who have decided to vote Conservative, although 56 per cent still have not made up their minds.

Labour's potentially improving prospects may be down in part to Jeremy Corbyn's performance, as 58 per cent of respondents in the region think he's had the best general election campaign. 

While 91 per cent of those planning to vote Labour think Corbyn has been having the best campaign, so do 70 per cent of Liberal Democrat voters and 47 per cent of Green voters, for both a bigger proportion than think the leader of the respective party they are backing is doing best. Of those planning to vote Conservative, 71 per cent think Theresa May has had the best campaign, while a fifth, 22 per cent, think Jeremy Corbyn's has been better.

Missing the leaders' debate on BBC1 last week may not have helped the perception of May's performance, as 61 per cent of respondents said it was the wrong decision, including 89 per cent of those planning to vote Labour, 86 per cent of those backing the Liberal Democrats and even 25 per cent of Tory voters, although 57 per cent of this group think she was right to skip the debate.

However, the survey suggests the debates had only a limited impact on how people are planning to vote, with just 8 per cent of respondents saying it had caused them to change their vote. People now planning to vote Liberal Democrat were the most likely to say they had changed their vote as a result of the debates, 16 per cent, followed by Labour at 11 per cent.

Labour voters were the most likely to feel more fired up as a result of the debates, with 40 per cent saying they had made them even more determined to vote for their party, compared to 19 per cent of Conservative voters saying the same.

Most respondents, at 63 per cent, said the party they were voting for was most important, rather than the 23 per cent who said it was the party leader, or the 14 per cent who were voting for their local candidate. Party was particularly important for those planning to vote Labour, 71 per cent put it top compared to 60 per cent of those planning to vote Conservative. Theresa May's campaign, which has more strongly focused on her, seems to have had an impact, with 33 per cent of those planning to vote Tory saying the leader of the party was the most important thing to them.

Social care and the NHS are the issues most likely to determine how a third of respondents are planning to vote, with 34 per cent saying it was most important, including 53 per cent of those planning to vote Labour and 39 per cent of Liberal Democrat voters. That was followed by Brexit, the key issue for 24 per cent of respondents, including 53 per cent of Conservative voters and 36 per cent of UKIP voters.