An appeal against the conviction of the late Abdelbaset al-Megrahi for the Lockerbie bombing has been formally lodged at the High Court.

The Scottish Criminal Cases Review Commission (SCCRC) referred the case to the High Court in March, ruling a possible miscarriage of justice may have occurred.

Now, lawyer Aamer Anwar, who made the SCCRC application on behalf of Megrahi’s family, supported by some families of those who died in the 1988 disaster, has confirmed “substantial” grounds of appeal have been lodged with the court.

In a statement, he said he expects five senior Appeal Court judges will hear the case later this year.

The bombing of Pan Am flight 103, travelling from London to New York on December 21 1988, killed 270 people in Britain’s largest terrorist atrocity.

Former Libyan intelligence officer Megrahi – found guilty in 2001 of mass murder and jailed for life with a minimum term of 27 years – was the only person convicted.

He died in 2012 after being released from prison early on compassionate grounds.

“We have now formally lodged with the High Court of Justiciary the appeal grounds in the posthumous appeal on behalf of the late Al-Megrahi,” Mr Anwar said.

“The reputation of the Scottish law has suffered both at home and internationally because of widespread doubts about the conviction of Mr Al-Megrahi.

“It is in the interests of justice and restoring confidence in our criminal justice system that these doubts can be addressed, however, the only place to determine whether a miscarriage of justice did occur is in the appeal court, where the evidence can be subjected to rigorous scrutiny.”

Megrahi’s son, Ali Al-Megrahi, said: “The family of my late father, ‏ Abdelbaset Ali Al-Megrahi and I wish to extend gratitude to our lawyer Aamer Anwar for the great efforts he has made in bringing this case to the appeal court and for the dedication of his legal team.

“‏We hope from God Almighty that success will be your ally in all your steps and that you will continue along this path.

“The legal team has made great efforts and is still making in exposing the unfair trial that my father was subjected to and continues to face despite his death.

“We have faith that justice will win in the end and overturn the unlawful verdict.”

The SCCRC published a decision on March 11 ruling a miscarriage of justice may have occurred in his case on two of the six grounds it considered in the review – unreasonable verdict and non-disclosure.

On the issue of unreasonable verdict, the commission said a miscarriage of justice may have occurred because no reasonable trial court, relying on the evidence led at trial, could have held the case against Megrahi was proved beyond reasonable doubt.

On the issue of non-disclosure, it said the Crown ought to have disclosed certain information to the defence and also its failure to disclose information about reward money bolsters the conclusion he was denied a fair trial.