Ukip leader Paul Nuttall has been hit with a fresh blow as his party has slipped to single digits in YouGov's latest opinion poll, released on Wednesday (15 March). The last time the Eurosceptic party was that low in YouGov's series was four years ago in February 2013.

The poll put the Conservatives on 44% (unchanged), Labour on 27% (+2), the Liberal Democrats on 10% (unchanged) and Ukip on 9% (-2).

The figures come in the wake of Nuttall's failure to win the Stoke-on-Trent Central by-election in February and as the party faces new in-fighting. Former Ukip donor Arron Banks said he split from the party after his membership lapsed.

"Ukip has somehow managed to allow my membership to lapse this year despite having given considerably more than the annual membership fee over the past 12 months," he said.

"On reapplying I was told my membership was suspended pending my appearance at a NEC [National Executive Committee] meeting. Apparently, my comments about the party being run like a squash club committee and Mr Carswell have not gone down well.

"I now realise I was being unfair to squash clubs all over the UK and I apologise to them. We will now be concentrating on our new movement."

The poll also showed that the Conservatives were 17 points ahead of Labour as Theresa May plans to invoke Article 50 of the Lisbon Treaty and trigger Brexit talks.

The prime minister told MPs on Tuesday that the Article 50 bill will receive Royal Assent and pass into law over the "coming days", while Jeremy Corbyn has promised to oppose a "bargain basement Brexit".

"It is deeply disappointing that the government has denied the British people, through Parliament, greater oversight over the Brexit negotiations and refused to guarantee the rights of EU citizens, who have made their lives in the UK," the left-winger said.

"We will continue to demand that the stress they, and British citizens living in the EU, are being put under is ended, and they are given the right to remain.

"Article 50 is being triggered because of the result of the EU referendum. But it is only the start of the process. Labour, at every stage, will challenge the government's plans for a bargain basement Brexit with Labour's alternative of a Brexit that puts jobs, living standards and rights first."