JAILED Liverpool fan Michael Shields must wait to learn whether he has won his High Court battle to be granted a free pardon.

Two senior judges were asked yesterday to rule that Justice Secretary Jack Straw has the power to exercise the ancient “Royal prerogative of mercy”, even though Shields was convicted abroad. They reserved their decision to a later date.

Shields, 22, is serving a 10-year sentence for the attempted murder of a barman at the Big Ben diner in Varna, Bulgaria, in 2005.

MPs, clergymen, Liverpool FC players and many others have backed the call to free him on the basis that he is innocent.

The barman was attacked a few nights after Liverpool’s European Cup Final victory in 2005.

Shields was initially jailed for 15 years in Bulgaria, but was transferred to the UK in 2006.

He is serving the remainder of his sentence, which was cut to 10 years on appeal in Bulgaria, at HMP Haverigg in Cumbria.

Mr Straw’s legal team argued there was no jurisdiction to grant him a free pardon.

They warned that, if the Justice Secretary did intervene, the move could be seen as criticism of the foreign court that had found Shields guilty.

That could “drive a very big hole” through the international convention on the transfer of prisoners that allowed convicts to serve their sentences in their home countries.

Lord Justice May and Mr Justice Maddison, sitting in London, reserved judgment and will give their decision in writing at a later date.

Family solicitor John Weate said after a day of legal argument: “We are very encouraged by how the hearing went today.

“We are encouraged also by the fact that the court has had to reserve judgment because constitutionally it raises an important point.”

The Liverpool fan has always vehemently maintained his innocence, and Fair Trials Abroad described his conviction - based solely on identification evidence with no supporting testimony - as a blatant miscarriage of justice.