The UK could be heading for a split from the EU after a late surge in support for the Brexit campaign – as three of four recent polls point towards a Leave vote – with just a week to go before the 23 June referendum. The latest telephone opinion poll from Ipsos Mori for The Evening Standard, of more than 1,200 people between 11 and 14 June, put Leave on 53% (+10) and Remain on 47% (-10).

The research also revealed concerns over immigration were driving UK voters towards backing a Brexit. The poll showed the issue had climbed to 33% (+5), while the economy had fallen to 28% (-5).

The survey makes grim reading for Remain campaigners David Cameron and George Osborne. Only 17% of UK voters believed the Chancellor's warning that households will lose on average £4,300 if they leave the EU, while 47% of respondents believe chief Vote Leave spokesman Boris Johnson's claim that Britain sends the EU £350m a week.

The figure, which was painted onto Vote Leave's battle bus, has been branded "potentially misleading" by the UK Statistics Authority since it does not take into account Britain's rebate from EU.

The Ipsos Mori survey comes after numerous other opinion polls have recorded a surge for Leave. A ComRes poll for The Sun, of more than 1,000 people between 9 and 13 June, put Remain on 46% (-6) and Leave on 45% (+4), with 9% of respondents undecided.

A YouGov survey for The Sun, of more than 1,900 people between 12 and 13 June, put Remain on 39% (-3) and Leave on 46% (+3), with 7% of respondents undecided. But Ukip leader Nigel Farage denied the Leave campaign had the referendum wrapped up, when IBTimes UK joined him on the campaign trail.

"Markets move, things change. Anyone in the Brexit camp who thinks we are there yet would be a fool," the Eurosceptic firebrand declared.