Two Hampshire men jailed over a £1.75 million Heathrow warehouse heist after being found guilty in a historic trial without a jury are appealing against their convictions today.

John Twomey, and Glenn Cameron were convicted with Peter Blake and Barry Hibberd in March by a judge at the Old Bailey.

They now argue that their trial was ''unlawful''.

Their trial in relation to an armed robbery at the warehouse in February 2004 was the first serious criminal trial to be held without a jury in England and Wales.

Three judges in the Court of Appeal in London are now being urged to find that their convictions are ''unsafe''.

The Lord Chief Justice, Lord Judge, sitting with Mrs Justice Rafferty and Mr Justice Roderick Evans, today lifted an order which had previously prevented reporting of the case.

Proceedings were due to begin at the Royal Courts of Justice this morning, with the four appellants present in the dock of courtroom number four.

But due to security concerns relating to that courtroom the case has been transferred to the Old Bailey, where it will be heard later today and is expected to last for three days.

Lord Judge said that ''one of these appellants has escaped from custody in the past'' and a condition of their presence for their appeal was that there should be ''no security problems''.

He added that ''our attention has been drawn to the fact that the physical arrangements in this court are inadequate to cope'' unless orders were made for the men to be handcuffed which was regarded as ''undesirable''.

A non-jury trial in their case took place after the Court of Appeal ruled there was a serious danger that a jury could be nobbled.

There had been three previous abortive attempts to try the case, lasting up to six months at a time.

The total cost to the taxpayer was estimated to be at least £25 million - more than 14 times the amount stolen.

At the end of the fourth trial, Mr Justice Treacy passed guilty verdicts on Twomey, 62, of New Milton, ; Blake, 57, of Notting Hill, west London; Hibberd, 43, of Shepherds Bush, west London; and Cameron, 50, of New Milton.

Twomey was sentenced to 20 years and six months. Blake was jailed for life with a minimum term of 10 years and nine months.

Cameron and Hibberd were sentenced to 15 years and 17 years and six months respectively.