Reform UK could make a comeback in the opinion polls if Nigel Farage is cleared in the row over his finances, according to Professor Sir John Curtice.
The party slipped below Labour this week after leading hundreds of consecutive opinion polls. Sir John said Labour was enjoying a bounce following Sir Keir Starmer's resignation and Andy Burnham taking over as prime minister.
Two separate factors
Sir John said Reform's decline had begun before Mr Burnham took over, with support falling after stories about Mr Farage's finances and donations to the party.
He said: "There are two separate things going on. One is that support for Reform is down but that predates the arrival of Burnham and it seems to be tied to Farage's response to the stories about various allegedly somewhat debatable ways of funding Reform or Nigel Farage's personal expenses."
"You can see very clearly either side of July 6, which is the day Farage said he was going to fight the by-election, support for Reform falls by about three points. So Reform were already down."
"Then if you compare Labour's position now which is 25% with where they were at immediately before Starmer announced his resignation which is 19% then there is a combined Starmer resignation/Burnham arrival bounce because some of it kicks in after Starmer's resignation."
Typical mid-term bounce
Sir John said the bounce was not unusual. He said: "This is pretty much par for the course. Gordon Brown actually got seven points when he replaced Blair. With the exception of Liz Truss, every single change of prime minister in mid-term has been accompanied by a bounce, typically around three or four points. So this one may be a little bit bigger but it's not unprecedented, I think Johnson got six or seven."
"The two crucial questions are does it go any further and for how long, if at all, is it sustained. Those are the questions we don't know the answers to."
"Meanwhile, there is a question mark about whether or not Farage and Reform can escape the damage that's seemingly been done so far to their reputation in the eyes of some of the electorate in the wake of the various stories that have been kicking around."
Investigations into Farage's finances
Sir John said the outcome would depend on the findings of the investigation by Parliament's standards commissioner over the undeclared £5 million gift Mr Farage received from crypto billionaire Christopher Harborne.
The Reform leader, who denies any wrongdoing, is also facing questions about financial support from his longtime friend George Cottrell, a convicted fraudster known as "Posh George", before entering Parliament.
The Met Police is looking into Reform's funding after Mr Cottrell is said to have transferred more than two million dollars to his mother Fiona Cottrell before she donated to the party in 2024. Reform has said all electoral rules were followed.
Sir John added: "Until we know the answers we won't know whether or not these stories really are going to bite Reform or whether it's going to blow over."
Conservatives more likely to benefit
Sir John said the Conservatives were more likely to benefit from Reform's polling decline than Labour.
He said: "The Tories are at 20%, which is a record high for about 12 months. Essentially while Labour do indeed get some benefit from the decline in Reform support, the Tories definitely do."
"Inevitably if Reform hit trouble, it's the Tories who are more likely to benefit because far more of Reform's support is ex-Tory voters."
Recent poll standings
A poll by More in Common put Labour on 28%, ahead of Reform on 24%, while Survation gave Labour 26% over Reform on 24%, and a YouGov survey showed the two parties tied.
