Twenty-five relatives of the Lockerbie bombing victims have agreed to support a new application to clear the name of the only man convicted.
They will give the Scottish Criminal Cases Review Commission (SCCRC) their new application in the next few weeks to try to overturn the conviction.
It has been prepared by legal expert Prof Robert Black.
The Crown Office said it would "rigorously defend" Abdelbaset al-Megrahi's conviction.
He was the only man convicted of the 1988 bombing which killed 270 people, died in 2012.
The application will focus on new evidence garnered since he dropped his appeal almost five years ago and the six grounds on which the SCCRC concluded it might have been a miscarriage of justice in its previous 2007 report.
Megrahi dropped his appeal to expedite his return home to Tripoli after he learned he had terminal cancer.
He was released from Greenock prison in August 2009 on compassionate grounds and died in Libya two years ago.
Dr Jim Swire and John Mosey both lost children in the tragedy.
They met with Prof Black in Glasgow to finalise the plans for the application.
Any applicant must have a "legitimate interest" in the case and the SCCRC would normally consult the deceased's family before accepting an application.
The BBC understands that Megrahi's family have given their tacit approval.
Last year Megrahi's brother Abdel-Hakim al-Megrahi told the BBC they wanted a "fresh appeal and for the truth to be revealed".
Dr Swire, whose daughter Flora died in the bombing, said he was confident the SCCRC would be sympathetic to a request from UK relatives of Lockerbie victims.
He said the relatives wanted answers.
"I have a privilege of representing about 25 British relatives," Dr Swire said.
"These are people who want to know the truth about who murdered their family. They want the public to know the truth about how, they believe, they have been deliberately kept from knowing the truth themselves by our government."
If the commission agrees to review the application and agrees the conviction could constitute a miscarriage of justice, they would then refer the case to the High Court.
The court could agree to hear the appeal or veto the referral.
'Interests of justice'
Gerard Sinclair, chief executive of the SCCRC, said: "There are several important matters which will clearly affect the timescale within which the commission will be able to deal with a fresh application.
"Even before deciding whether to accept this new application for review, the commission will require to consider a number of preliminary matters relating to the application.
"These include whether Dr Swire has a 'legitimate interest' to pursue, on behalf of Mr Megrahi, an application to the commission and any subsequent appeal. In order to address this matter the commission may require to petition the High Court for a formal opinion.
"If it is decided that Dr Swire has a 'legitimate interest' in this matter, the commission will also require to address whether it is 'in the interests of justice' to accept for a further review the conviction of Mr Megrahi. Consideration of these matters could take some time."
A Crown Office spokesman said: "We do not fear scrutiny of the conviction by the SCCRC.
"The evidence upon which the conviction was based was rigorously scrutinised by the trial court and two appeal courts after which Megrahi stands convicted of the terrorist murder of 270 people.
"We will rigorously defend this conviction when called upon to do so. In the meantime we will continue the investigation with US and Scottish police and law enforcement."