Justice Secretary Liz Truss is locked in an extraordinary stand-off with England’s most senior judge, after he slammed the brakes on her plans to spare alleged rape victims cross-examination in court.

Ms Truss is under growing pressure after the Lord Chief Justice, Lord Thomas of Cwmgiedd, said she was “wrong” to announce the dramatic change to sex crime cases.

On Monday, the Justice Secretary told MPs that the playing of pre-recorded evidence to juries would begin in September, after “senior judges agreed to accelerate the scheme”.

But Lord Thomas said her department had “misunderstood the thing completely”, forcing him to write to all judges to correct the mistake.

“It was a complete failure to understand the impracticalities of any of this. And that is very troubling,” he told an inquiry by a House of Lords committee.

In fact, only child witnesses would give pre-trial evidence on videotape – alongside a trial in three centres for alleged adult victims of sexual offences, Lord Thomas said.

However, Downing Street stood by Ms Truss, insisting the policy would go ahead as she had described.

“The Government’s position has not changed on this, the new measures will be rolled out from September,” a spokesman said.

“We have always been clear that there will be a pilot in those three centres which will inform a national rollout.”

The spokesman insisted the Prime Minister had full confidence in Ms Truss – and that he believed the legal profession had full confidence in her.

But Tim Farron, the Liberal Democrat leader, said: “We have a Justice Secretary who is just not up to the job. Useless, clueless and has lost the respect of the judiciary.

“Liz Truss needs to take responsibility for the utter shambles that is her department. She cannot pass the buck like she is. Enough is enough.”

The clash came after Ms Truss, who is also the Lord Chancellor, said she was expanding a trial underway – for children only – at the three courts in Liverpool, Leeds and Kingston-upon-Thames in Surrey.

“We are bringing forward the roll-out of reforms to allow rape victims to pre-record their cross examination, sparing them the trauma of giving evidence during trial,” MPs were told.

Senior judges had been “vital in developing the plans for rolling out these provisions for child victims and victims of sexual offences in all Crown courts”.

But, two days later, Lord Thomas told the House of Lords Constitution Committee he had been forced to “correct a serious misapprehension”.

It was wrong to talk of a national scheme because “we want to roll it out carefully, it is quite difficult changing the culture”, he said.

In a damning criticism, the Lord Chief Justice added: “The Ministry of Justice is under-resourced. They do not have enough people who understand.”

The Truss announcement was also criticised by a men’s support group, which claimed it would prejudice cases against defendants.