John Stevenson will not be prosecuted over the Conservative Party's 2015 Battlebus general election expenses.

Mr Stevenson, who was Carlisle's MP, was among more than 30 people nationally who were at risk of criminal charges as a result of a probe into whether they knowingly broke the rules governing election expenses.

Mr Stevenson - currently campaigning to be reelected as the city's MP on June 8 - was told today that he and his agent during the last election John Mallinson, who leads the Conservatives at Carlisle City Council, will not be prosecuted.

Mr Stevenson said: “I'm delighted that the Crown Prosecution Service (CPS) has confirmed that they will not be pursuing me or John Mallinson, and in all honesty I never expected to be charged.

“I would have been gobsmacked if they had charged us.

“We submitted what we honestly believed were true and correct accounts. The Battlebus was considered to be a national expense by our national party and we have written confirmation from our HQ that that was the case.

“Obviously, it's a relief, but I'm pleased that the CPS have acknowledged that John and I did absolutely nothing wrong.”

All politicians have to abide by strict spending limits so that those backed by wealthier parties do not have an unfair advantage.

The expenses investigation has focused on whether the Conservative Battlebus campaign, which took activists to key marginal constituencies – including Carlisle – was illegally recorded as a national rather than a local expense.

Mr Stevenson has consistently said he did nothing wrong.

In earlier statements, he said he did not believe his party intentionally did anything wrong in its handling of the 2015 general election expenses.

He suggested that a failure to correctly record accommodation expenses of activists following the Battlebus was down to “administrative error.”

The Tories had insisted the Battlebus, which visited Carlisle, was overseen by officials at Conservative Campaign HQ, and thus associated expenses should not have been part of any candidate's campaign expenses.

Earlier this year, the Conservative Party was fined £70,000 for failing to accurately report on how much it spend on campaigning in three by-elections in 2014, and during the 2015 General Election.

There have been fears that any potential prosecution of current Conservative candidates in the June 8 General Election could throw the party's campaign into chaos, and neccessiate finding new candidates.

Police in several areas of the country – including Cumbria – submitted files following the investigation to the Crown Prosecution Service for a decision on whether charges should be brought.

Nick Vamos, who leads the CPS's Special Crime Unit, said: “We have considered files of evidence from 14 police forces in respect of allegations relating to Conservative Party candidates’ expenditure during the 2015 General Election campaign.

“We considered whether candidates and election agents working in constituencies that were visited by the Party’s ‘Battle Bus’ may have committed a criminal offence by not declaring related expenditure on their local returns. Instead, as the Electoral Commission found in its report, these costs were recorded as national expenditure by the Party.

“We reviewed the files in accordance with the Code for Crown Prosecutors and have concluded the tests in the Code are not met and no criminal charges have been authorised.

“Under the Representation of the People Act, every candidate and agent must sign a declaration on the expenses return that to the best of their knowledge and belief it is a complete and correct return as required by law. It is an offence to knowingly make a false declaration. In order to bring a charge, it must be proved that a suspect knew the return was inaccurate and acted dishonestly in signing the declaration. Although there is evidence to suggest the returns may have been inaccurate, there is insufficient evidence to prove to the criminal standard that any candidate or agent was dishonest.

“The Act also makes it a technical offence for an election agent to fail to deliver a true return.

"By omitting any ‘Battle Bus’ costs, the returns may have been inaccurate. However, it is clear agents were told by Conservative Party headquarters that the costs were part of the national campaign and it would not be possible to prove any agent acted knowingly or dishonestly. Therefore we have concluded it is not in the public interest to charge anyone referred to us with this offence."

He said the CPS's evaluation of the evidence was consistent with that of the Electoral Commission.

He added: "While the role of the Commission is to regulate political finances and campaign spending, the role of the CPS is to consider whether any individual should face criminal charges, which is a different matter with different consideration and tests.

“One file, from Kent Police, was only recently received by the CPS, and remains under consideration.

"No inference as to whether any criminal charge may or may not be authorised in relation to this file should be drawn from this fact and we will announce our decision as soon as possible once we have considered the evidence in this matter.”