The controversial methods, which include the "tantrum hold", "nose distraction" and "wrist lock", were heavily criticised after the death of teenager Gareth Myatt in Rainsbrook Secure Training Centre in Northamptonshire.

After an inquest, two of the most severe restraints were suspended pending a review, but High Court judges have now criticised Secretary of State Jack Straw's decision to allow physical deterrents to be used as punishment by guards.

High Court Judge Lord Justice Maurice Kay said the new rules represented a significant change in the way prison staff could use the methods. He said: "There is something unattractive about the stance of the Secretary of State.

"We unhesitatingly characterise that as a significant change of policy, and we do not consider that the Secretary of State, if he had applied his mind to it, could reasonably have seen it in any other way."

The Children's Commissioner Prof Sir Al Aynsley-Green took the Government to the High Court after he was not consulted on the change to legislation, where Jack Straw was criticised by the two judges.

Previously, guards were only permitted to use the techniques when young people in secure training centres "kick off" or cause trouble, as a way of bringing them under control. It has now been alleged staff are routinely using them as disciplinary actions.

The review was prompted following the death of Gareth Myatt, who died after choking on his own vomit while being held in an embrace, despite warning guards he was unable to breathe.

Campaigners claimed victory when two restraints were suspended last December but Northampton North MP Sally Keeble, who led a campaign for reform, said at the time that all physical restraints should be stopped.