The plane was diverted to Stansted

The three judges at the Court of Appeal said on Friday a mistake in directing the jury was the only reason the men's appeal had succeeded.

The Tories have claimed the men's successful appeal against their convictions last month sent out a dangerous message to would-be hijackers, the Tories claimed.

The original trial of the men was told that during the three-day siege at Stansted Airport in February 2000 they had threatened to murder passengers and crew.

They were jailed at the Old Bailey in 2001 for hijacking an Afghan Ariana Boeing 727 on an internal flight in Afghanistan.

We do not for a moment accept that the success of this appeal is a charter for future hijackers Lord Justice Longmore

The convictions were quashed as "unsafe" last month after the judges heard that the law relating to whether the nine acted under "duress" because of their professed fear of the brutal Taleban regime had been wrongly applied at their Old Bailey retrial.

"The only reason this appeal has succeeded is that there was a misdirection in relation to the law as explained to the jury," said Lord Justice Longmore, sitting with Mr Justice Hooper and Mrs Justice Cox.

He added: "In the light of some of the newspaper comments on the announcement of our decision, we think it right to say that we do not for a moment accept that the success of this appeal is a charter for future hijackers."

Served sentence

Shadow transport secretary Tim Collins said last month that whatever pressure the hijackers had been under, it did not justify "putting people's lives at risk".

"My concern is that this may be sending out a signal that somehow Britain has become a soft touch on hijacking, which, of course, would put both UK airlines and UK airports at risk," he said.

Brothers Ali and Mohammed Safi - who led the hijack and were jailed for five years - were the only men still in jail at the time of the court's ruling.