The UK is heading for a split from the EU in just nine days' time as support for a Brexit strengthens, according to the most recent opinion polls. The latest YouGov survey for The Times, of more than 1,900 people between 12 and 13 June, put Leave on 46% (+3) and Remain on 39% (-3), with 11% of respondents undecided.

Separate opinion polls by ICM for The Guardian, conducted online and over the phone, put Leave on 53% (+1) and Remain on 47% (-1). The findings are expected to make worrying reading for the pro-EU Prime Minister David Cameron and the rest of the Remain campaign, including Labour, the Liberal Democrats and the SNP.

Former Labour Prime Minister Gordon Brown relaunched his party's pro-EU campaign on 13 June, amid fears that Cameron's prominence in the EU referendum campaign could turn Labour voters off.

Jeremy Corbyn, Labour's left-winger leader, will also make another intervention in the campaign when he appears alongside his shadow cabinet at Trades Union Congress (TUC) house in central London on 14 June.

"Today sees my shadow cabinet and the trade union movement join together, in the interests of the people of this country, to make Labour's case to remain in the European Union and bring reform to strengthen workers' rights," Corbyn will say.

"That's why today I am issuing a call to the whole Labour movement, to persuade people to back Remain to protect jobs and rights at work. We have just nine days to go to convince Labour supporters to vote Remain."

The Remain campaign have made a number of warnings about the economy in the run-up to the 23 June vote, but Brexit backers have decided to highlight the issue of immigration, a move which has seen Vote Leave adopt Ukip's policy of supporting an Australian-style immigration points system.

The Brexit campaign was also boosted after The Sun, the UK's most popular tabloid newspaper, threw its support behind a Leave vote on 14 June.

"Vote Leave and we will reassert out sovereignty – embracing a future as a self-governing, powerful nation envied by all. We will re-establish the basic principle that we are governed by politicians we elect or eject every five years, not foreign bureaucrats," the front-page of the Rupert Murdoch-owned title declared.