The change had the effect of pushing war crimes allegations against the SAS outside the cut off period for bringing a prosecution under normal circumstances.

Sir Ben Wallace knew that allegations about the killings of Afghan civilians by SAS forces were “broadly accurate” four years before ordering a public inquiry, a hearing was told.

Giving evidence at the High Court, Ben Wallace fired back at Johnny Mercer who previously suggested he had shown a 'lack of curiosity' about the allegations.

The former defence secretary answers question at the inquiry investigating claims made in a BBC Panorama programme that Afghan civilians were executed by three SAS squadrons between 2010 and 2013 - before Sir Ben took responsibility for the Ministry of Defence (MoD).