Labour has called for prosecution powers to be stripped from the Post Office and previous convictions looked at again, amid growing anger over the wrongful prosecution of subpostmasters and postmistresses for alleged fraud.

It comes as MPs plan to raise the Horizon scandal in the Commons as Parliament returns this week, with Conservative backbencher David Davis and Labour MP Kevan Jones pushing for an emergency debate after an ITV drama returned the widespread miscarriage of justice to the spotlight.

Sir Keir Starmer, speaking during a visit in Loughborough, said: “I think that the prosecution should be taken out of the hands of the Post Office and given to the Crown Prosecution Service.

“I used to run the Crown Prosecution Service, we’ve prosecuted for other departments, we can do it here – that should be done straight away.

“And these convictions, the remaining convictions need to be looked at en masse.”

He added: “The Government could pass legislation, so obviously we’d support that if they did.

“It might be possible to get these cases back before the Court of Appeal quickly – I’ve done that when I was a prosecutor – but whichever way it’s done, these convictions need to be looked at.”

Justice Secretary Alex Chalk is expected to meet Post Office minister Kevin Hollinrake on Monday to discuss how to help the convicted branch managers clear their names.

Mr Hollinrake, in a post on social media, said 100% of known victims of the scandal have received “interim payments of up to £168k, 100% of those in the original Horizon Shortfall Scheme have received offers (>80% have accepted), 64% of all known victims have accepted full settlement”.

But he said he is “working day and night to do more”.

The Prime Minister, speaking in Accrington, Lancashire, on Monday, defended the Government’s response but said he wants to speed up the compensation process.

“People should know that we are on it and we want to make this right, that money has been set aside,” he said.

“We will do everything we can to make this right for the people affected. It is simply wrong what happened. They shouldn’t have been treated like this.”

As MPs return to Westminster, former Tory minister Mr Davis stressed it was down to Commons Speaker Sir Lindsay Hoyle to grant urgent questions from MPs but he believed there was “no doubt” the issue would come up in the chamber in the coming days.

“This is such a big issue. There are now tens of millions of people who care about this, and care about it a lot,” he told BBC Radio 4’s Today programme.

“It did take a docudrama in this case I’m afraid, and many of us have been struggling for a long while to try and elevate it.”

More than 700 Post Office branch managers were given criminal convictions after faulty Fujitsu accounting software called Horizon made it appear as though money was missing from their shops.

Treasury minister Bim Afolami said Mr Chalk was “urgently” looking at how to accelerate the “slow wheels of justice” and warned that senior Post Office executives from the period will need to account for their actions.

It comes as calls grow for former Post Office chief executive Paula Vennells to hand back her CBE.

Mr Sunak and Labour leader Sir Keir have so far resisted backing calls for the former Post Office chief to lose her honour.

But shadow environment secretary Steve Reed said on Monday the honour is an “insult” to victims and should be handed back. A petition calling for Ms Vennells to be stripped of the CBE attracted more than one million signatures.

Ms Vennells, who ran the Post Office while it routinely denied there was a problem with its Horizon IT system, has said she was “truly sorry” for the “suffering” caused to subpostmasters who were wrongly convicted of offences.

Lord Arbuthnot, who was an MP at the time of the scandal, said Parliament should work to see that the miscarriage of justice is dealt with in a “mass way”.

We've seen the way that investigators behaved and they behaved in a way which was contrary to the rule of law. These convictions have got to be set aside

Meanwhile, Labour MP Mr Jones, who is a member of the Horizon compensation advisory board, said a “number of individuals” should be prosecuted over the scandal.

Another member of the board, Professor Richard Moorhead, predicted people would be charged over the scandal as Scotland Yard probe potential fraud offences arising out of the initial prosecutions.

There has been fresh public backlash to the scandal after ITV aired a drama about the scandal last week starring actor Toby Jones.

Reports suggest since Mr Bates Vs The Post Office was broadcast, 50 new potential victims have approached lawyers.

The Post Office is wholly owned by the Government and a public inquiry into Horizon is ongoing.

Scotland Yard said on Friday that officers are “investigating potential fraud offences arising out of these prosecutions”, for example “monies recovered from subpostmasters as a result of prosecutions or civil actions”.

The Metropolitan Police had already been looking into potential offences of perjury and perverting the course of justice in relation to investigations and prosecutions carried out by the Post Office.