Jeremy Corbyn's Labour Party faces some big branding issues which could stop the party winning the next general election, a top political expert revealed on Wednesday night (19 October).

The University of London's Professor Tim Bale, speaking at a Centre for Opposition Studies event, also warned Labour's lack of cohesion could prove detrimental at the ballot box.

"Parties that win from opposition are usually able to present a sense of cohesion to the public. That is clearly something Jeremy Corbyn's Labour Party are unable to do," he said. "They are, of course, facing a Conservative Party haven't always been able to do either."

Bale added: "Successful oppositions have been to present a distinctive platform which captures the imagination of the electorate and also gains a certain amount of credibility among opinion formers in the media.

"At the moment that's not the case with the Labour Party, although there are some Labour policies that appeal to the average voter. Labour programme isn't more than the sum of its parts, it's less than the sum of its parts.

"You have polling already indicating that people are favourable to a particular policy until they hear it's a Labour Policy, and then their support for it reduces, which suggests Labour has a brand problem."

The analysis came just hours after a poll from Ipsos MORI for The Evening Standard, of more than 1,000 people between 14 and 17 October, showed the Tories were 18 points ahead of Labour (47% versus 29%).

Corbyn will hope to improve the party's standing with his shadow cabinet reshuffle, which he is currently finalising. The shake-up, among other things, has seen the return of Sir Keir Starmer to the front bench as the party's new shadow Brexit secretary.

But Bale warned previous reshuffles from Corbyn had failed to capture the public's imagination. "Successful oppositions] introduce fresh faces to the public to give the idea that the party is changing, that there is a new order," he said.

"You can say that Corbyn's Labour Party have been able to do some of this, but even those fresh faces at the moment haven't been there long enough for us to tell if they're any good and some, of course, have left before they have begun.

"The very top team of Labour Party – the shadow home secretary, the shadow chancellor and the shadow foreign secretary – there are people who are very familiar to the public and are not seen as particularly fresh or appealing."

Corbyn faces his first test since his re-election in the Witney and West Oxfordshire by-election today. The constituency is David Cameron's old seat and the Conservatives are expected to retain it.

Labour came second in the seat at the general election, but could be pushed into third place by the Liberal Democrats, who came fourth behind Ukip last time around. Polls close at 22:00 BST, with a declaration expected between 03:00 and 04:00 tomorrow.