Former subpostmaster and campaigner Alan Bates has said he will pursue private prosecutions against those responsible for the Horizon IT scandal if the inquiry does not pass a file to prosecuting authorities.

The inquiry resumed this week with Mr Bates giving evidence and on Friday he told the Times he would be willing to crowdfund criminal action against those responsible at the Post Office.

On BBC Radio 4’s Today programme he asked the inquiry to clarify if a file would be passed to prosecutors and police, and said members of Parliament should “change the remit of the inquiry” to ensure it is.

Mr Bates said prosecutions should be looked into immediately as an additional element to the inquiry which is due to finish in September, adding that a delay could mean “we have to start all over again”.

Metropolitan Police Commissioner Sir Mark Rowley told LBC in January that fraud offences may have been committed but an investigation could run until at least 2026.

On Saturday Mr Bates told the BBC: “If we find that the authorities, whoever it is, are not prepared to take this forward, I think it’s pretty certain that we’re going to have to look at private prosecutions.

“It was fine when Post Office brought private prosecutions so if we’ve got to do it in return then so be it.”

He added: “What is going to be the extent of (the Met’s) investigation? Is it just the fraud cases or is it going to look at all issues that might have affected the whole of this?”

Asked if he was calling for private prosecutions to “put pressure on police and the inquiry”, he said: “I’m hoping to bring clarity to the issue.

“We heard from many, many lawyers along the way that there does seem to be quite a number of cases for people to answer.”

He said people want to see “accountability” as well as financial redress.

The campaigner said he was glad he gave evidence first and “got it out of the way” to allow the inquiry to “find the real villains in all of this”.

“I think we’ve now got to the stage that those who actually were making decisions, and were responsible for decisions being made, are now being heard at long last.

“We’re hoping to see the truth. I’m not sure we will, but what we’ve always campaigning for is to expose the truth of the whole matter.

“They are testifying on oath, and for whatever reason there does seem to be some gaps in memories – and I know quite a lot of it does go back some time.

“Also I think also quite a lot of documentation might well have disappeared over the years as well, but all we can do is keep our fingers crossed.

“In fairness there has also been quite a lot of build-up over the past couple of years with the inquiry, so hopefully there is enough evidence to put to them.”

Mr Bates had his contract terminated by the Post Office in 2003 after refusing to accept liability for shortfalls in the accounts at his branch in Llandudno, North Wales.

The inquiry heard he first raised issues with the Horizon system in 2000, and on one day in December of that year he called the Post Office helpline seven times, with one call lasting around an hour.

Giving evidence in front of Post Office chief executive Nick Read on Tuesday, Mr Bates said it was “an atrocious organisation” that was “beyond saving” and needed “disbanding”.

The Post Office has come under fire since the airing of the ITV drama Mr Bates Vs The Post Office, which put the Horizon IT scandal under the spotlight.

More than 700 subpostmasters were prosecuted by the Government-owned organisation and handed criminal convictions between 1999 and 2015 as Fujitsu’s faulty Horizon system made it appear as though money was missing at their branches.