Veterans’ minister Johnny Mercer will no longer have to meet Friday’s deadline to hand over the names of those who told him about alleged special forces murders in Afghanistan.

Sir Charles Haddon-Cave, chairman of the Afghanistan Inquiry, gave Mr Mercer until 4pm on April 5 to provide a witness statement containing the names or face a potential prison sentence.

This deadline has now been extended while the chairman considers Mr Mercer’s application to challenge the order and PA understands a decision could take at least a week to be reached.

During Mr Mercer’s evidence to the inquiry last month, the chairman said his decision to “refuse to answer legitimate questions … at a public inquiry” were “disappointing … surprising … and completely unacceptable”.

This came after Mr Mercer repeatedly refused to hand over names of “multiple officers” who told him about allegations of murder and a cover-up, during his time as a backbench MP.

On Tuesday, the MP for Plymouth, Moor View posted on X, formerly Twitter: “I am aware of tomorrow’s deadline from the Afghan Inquiry order that requires me to name the whistleblowers who confided in me.

“I am submitting an application to challenge the order under section 21(4) of the Inquiries Act 2005 seeking to have the Section 21 notice set aside.

“It would not be appropriate to comment further.”

Giving his reason for not disclosing the names, he told counsel to the inquiry Oliver Glasgow KC last month: “The one thing you can hold on to is your integrity and I will be doing that with these individuals.”

The inquiry said Mr Mercer was served with a Section 21 notice on March 13, compelling him to hand over the names, which the inquiry has said will be “treated in confidence”.

In the order, the chairman said the consequences of failing to comply without reasonable excuse would be “a criminal offence punishable with imprisonment and/or a fine”.