A MAN who admitted killing a father-of-four in a street attack yesterday tried to have his manslaughter conviction overturned at London's Appeal Court.

Carl Mason, of no fixed address, chased Michael Brolly through the streets of York on September 16, 2001, and then kicked and stamped him to death.

Mason, 23, admitted manslaughter but yeterday his legal team argued he should have been allowed to vacate his guilty plea in June 2002.

Mr Justice Treacy, who jailed Mason for four years, had declined his request to change his plea to not guilty - a decision which was attacked at the Court of Appeal by his counsel, Robert Smith QC.

Mr Smith said that key prosecution witnesses had been undermined shortly after the guilty plea was entered.

If he had been aware of what would happen at the time, Mason - who was originally charged with murder - would never have opted to plead guilty, said the barrister.

He only did so on the advice of his legal team, argued Mr Smith, as they were concerned at the strength of the witness evidence against him.

But James Goss QC, for the Crown, argued that the strength of the case was only one of the reasons why Mason owned up.

Mr Goss said Mason's legal team were also concerned at the much longer sentence he would be likely to receive if convicted of the murder charge.

Lord Justice Potter, who was hearing the case with Mr Justice Hunt and Mr Justice Tugendhat, said it was arguable that Mason should have been allowed to vacate his guilty plea.

Mr Brolly was attacked after being chased through York city centre, and was found unconscious by police on Low Ousegate.

The killing of the 34-year-old, of Margaret Street, Walmgate, York, was sparked after an incident in a city centre bar.

After listening to a day of legal argument, the judges reserved their decision on Mason's appeal to a later date.