Nigel Farage will restate his case for the UK leaving the European Union (EU) when the Ukip leader addresses his party's annual conference on 25 September. The Eurosceptic firebrand is also expected to deliver the keynote speech ahead of the UK's referendum on its membership of the 28-nation bloc, which David Cameron has promised to hold before the end of 2017.

Farage will promise to concentrate all of his political efforts on campaigning for Britain to break away from Brussels in the months ahead, rather than targeting the Welsh Assembly, Scottish Parliament, and local elections in 2016.

"But that is not where my priorities lie. I am more interested in winning the referendum. I'm not deserting the party but winning the referendum is absolutely key and that's where our energies must go," he will say, according to the Press Association.

The Doncaster Racecourse conference, held on the doorstep of former Labour leader Ed Miliband's constituency, will also give Farage and Ukip the opportunity to rally and rebound after the general election.

The Eurosceptics were winded after Farage lost out to the Conservatives in South Thanet. Mark Reckless, who defected from the Tories in 2014 and won back his Rochester and Strood seat in a crunch by-election, also failed to poll first. The disappointing results meant Douglas Carswell became Ukip's only MP after retaining his Clacton seat.

But the party did secure its strongest performance in a general election by attracting more than 12% of the vote and coming second in many seats across the country, including a strong turnout in the hitherto Ukip-light north of England.

The latest opinion poll from Ipsos MORI, which surveyed more than 1,200 voters between 19 and 23 September, put Ukip on just 7%. The results mean the Eurosceptics were behind the Liberal Democrats (9%), Labour (34%) and the Conservatives (39%).

Farage is expected to deliver his keynote at 12:00 BST and Ukip will announce its candidate for the Mayor of London election next year in the day. Suzanne Evans, the party's deputy chair, is among the hopefuls.