Judges from outside Scotland could be required to clear up the potential damage to the reputation of Scottish justice if the Lockerbie trial verdict is declared to be a potential miscarriage of justice this week.

That was proposed yesterday by Tam Dalyell, the former Labour MP for Linlithgow and a long-time campaigner for the verdict on Britain's worst case of mass murder to be reconsidered.

Yesterday he joined fellow campaigner Jim Swire, father of a victim of the bombing of PanAm flight 103, in calling on the SNP-led administration at Holyrood to call an independent public inquiry into the handling of the Lockerbie inquiry.

A spokeswoman for the administration said yesterday that it awaits Thursday's finding by the Scottish Criminal Cases Review Commission (SCCRC), adding: "It is the strong view of the Scottish government that due process of law will be followed and be seen to be followed in all matters pertaining to this case."

Mr Dalyell protests the innocence of Abdelbaset Ali Mohmed al Megrahi, the man found guilty of planting a bomb on the flight that blew up over Lockerbie in December 1988, killing 270 people. There is a growing expectation the SCCRC will conclude that there may have been a miscarriage of justice and refer the case to the Court of Appeal.

Mr Dalyell recently met the former Libyan intelligence officer at Greenock Prison, where he is serving 27 years. The former MP quoted him as admitting he had been breaking United Nations sanctions against Libya at the time of the bombing: "He said he was getting spare parts for Libya's oil industry and Libyan Arab Airlines, and that is why he travelled so much," said Mr Dalyell.

He argues that revelations about the weakness of the prosecution case will raise questions about the quality of the defence, and why there was so little challenge to the reliability of key witness Tony Gauci, who claimed to have seen Megrahi in Malta, but is alleged to have changed his version of events in crucial ways.

If the SCCRC comes out against the conviction, Mr Dalyell claimed: "It will be shattering for the whole system of Scottish justice."

It was claimed that too many senior judges have been involved in past proceedings on the Lockerbie bombing. "They should call in a couple of judges from another jurisdiction, and not necessarily England," said the former MP. "But of course, they have got to do it quickly."

Several newspapers yesterday published details of the appeal lawyers' case, much of it focusing on the pivotal evidence from the Maltese shopkeeper.

There were accusations that other vital evidence was lost, destroyed or tampered with, and that there was interference with the police inquiry and prosecution case on both sides of the Atlantic. There was also a claim that the SCCRC's finding, after three-and-a-half years, was reached 18 months ago but has been delayed.

The case carries a risk that an acquittal could lead the Libyan government to claim back the $2.7bn it paid to families of the Lockerbie victims, a bill that could come to the Scottish Executive.

Megrahi was the subject of the first spat between the SNP administration and Downing Street after Tony Blair last month signed a memorandum of understanding on prisoner transfer with Libyan leader Muammar Gaddafi but neglected to consult Scottish authorities in advance.