Subpostmasters in Northern Ireland and Scotland wronged in the Horizon scandal should have their convictions quashed in a Westminster law change because the “mess” was made there, ministers have heard.

The Post Office (Horizon System) Offences Bill would overturn the convictions of all subpostmasters in England and Wales related to the faulty Horizon accounting software.

Ministers have previously urged the devolved administrations in Holyrood and Stormont to take similar steps to quash convictions, because Scotland and Northern Ireland have their own legal systems.

But MPs from Scotland and Northern Ireland called for the Bill to cover all nations and regions of the UK.

I don't mind politicians taking responsibility for things that they have been responsible for. But this was not an issue that politicians in Northern Ireland or indeed in Scotland were responsible for

SNP frontbencher Marion Fellows said she was “deeply disappointed” the Bill did not apply to Scotland, adding: “The whole business of Horizon arose here under Post Office Limited, which is wholly owned by the UK Government, being the central shareholder. So there is a logic to saying the mess is made here, it should be cleared up here.”

She added: “I think it is becoming clear that I will be seeking to amend this Bill, I will be taking advice and I will attempt to do what will be done in Northern Ireland.”

Lib Dem MP Alistair Carmichael (Orkney and Shetland) suggested he was open to the Scottish Parliament to pass a similar Bill in as little as three days by an emergency process, but Ms Fellows said there was no guarantee this could happen.

He later said he was “open to be persuaded” on adding Scotland to the Bill’s remit, but said Horizon-related prosecutions north of the border had been carried out Scottish public prosecutors, rather than by the Post Office directly, as in England and Wales.

He insisted “accountability” in the justice system required the Scottish Parliament to pass its own law change, telling MPs: “I think that for quality of justice, that accountability, if it is achievable within the same timescale because we are balancing competing demands here, is very important.”

DUP MP Sammy Wilson (East Antrim) said: “I don’t mind politicians taking responsibility for things that they have been responsible for. But this was not an issue that politicians in Northern Ireland or indeed in Scotland were responsible for.

“The Post Office was not a devolved issue, it was reserved.”

His DUP colleague Ian Paisley (North Antrim) asked if Labour would support Northern Ireland being added to the remit of the Bill, telling the Commons: “I would appeal to the Opposition spokesman to support if a motion were to come forward to instruct the House to extend this Bill to cover Northern Ireland, would the Opposition support such a motion so that those fine words and good will are turned into strong action?”

Shadow business secretary Jonathan Reynolds replied: “I can tell colleagues the Labour Party does support those calls.

“I understand this would be a complex constitutional undertaking, but as I say given every party in Northern Ireland and every minister I believe in the new assembly are calling for their inclusion in this Bill, I think we have to recognise that.”

Post Office minister Kevin Hollinrake assured MPs that subpostmasters across the UK would all have the same access to compensation, no matter how their convictions were overturned.

He said: “The compensation schemes, whatever schemes they are on, and there are three: the Horizon shortfall scheme, group litigation order scheme and the overturning conviction scheme; are all UK-wide, so whatever detriment is experienced wherever they are in the UK, there is no difference in compensation in terms of one part of the UK to another.

“We are keen to expedite it wherever it is in the UK, and we have got work to do.”