Theresa May has backed Conservative MPs at the centre of police inquiries into electoral spending irregularities, after a call for them to be barred from standing for re-election.
Fourteen police forces have sent files to the Crown Prosecution Service outlining allegations of spending limits being breached during the 2015 general election campaign. The files are understood to refer to more than 30 individuals.
Some MPs could face the possibility of being charged with offences while they are in the middle of fighting their campaigns for re-election in June.
Dennis Skinner, the veteran Labour MP, said in the House of Commons that allowing Tory MPs currently under investigation to stand again risked bringing about “the most squalid election campaign that has happened in my lifetime”.
May replied: “I stand by all the Conservative MPs who are in this house and who will be out there standing again, campaigning for a Conservative government that will give a brighter and better future for this country.”
The SNP MP Stewart McDonald asked May: “Doesn’t it take some brass neck to call a general election when you are facing allegations of buying the last one?”
May brushed the question aside, saying it was “not worthy”.
The CPS is currently reviewing the evidence and considering whether to charge any MPs with breaching spending limits. The limits are intended to prevent candidates with wealthy backers from gaining an unfair advantage in elections.
A spokesperson for the CPS confirmed that any charges would have to be brought before the date of the election. All 14 police forces that sent files to the CPS last year applied for a 12-month extension to the prosecution deadline, which would have otherwise elapsed last summer.
Channel 4 News reported on Tuesday evening that the CPS was considering prosecuting more than 30 people.
Allegations highlighted by Channel 4 News and the Daily Mirror relate to busloads of Conservative activists sent to key seats, whose expenses were reported as part of national campaign spending rather than constituency spending, which has a lower limit.
Karl McCartney, the MP for Lincoln, and William Wragg, who represents Greater Manchester’s Hazel Grove, have confirmed their election expenses files were among those passed to the CPS.
In a statement to the Guardian this year, McCartney said: “There is an ongoing police investigation and, as such, I would prefer not to comment directly on that as it has yet to be concluded other than to say I know I have done nothing wrong and I acted honestly and properly throughout my election campaign, as did, very importantly, my election agent.”
Wragg said: “I was assured, at the time and now, that the battle bus was a national expense and my election agent was instructed by Conservative campaign headquarters to treat it as such.
“Accordingly, it was not declared locally, but was left for the party to declare nationally … I have cooperated fully with Greater Manchester police and I await the decision of the CPS as to whether to progress the case or not.”
Conservative MPs under investigation by the Electoral Commission include the former cabinet minister Anna Soubry, as well as Neil Carmichael, Kevin Foster, Marcus Fysh, James Heappey, Scott Mann and David Nuttall. However, they have not confirmed whether they are among those being considered by the CPS.
All deny wrongdoing and say they believed in good faith that the battle bus spending came under national campaigning budgets.