The Afghan inquiry has set a deadline of next week by when the veterans minister, Johnny Mercer, must reveal the names of the SAS whistleblowers who gave him sensitive information in confidence about the alleged murders of innocent people in Afghanistan. But today, The Times reported that sources close to Mercer have said he would be willing to go to prison before disclosing the names of the whistleblowers. In February, Mercer, a former officer, told the inquiry that special forces soldiers had raised concerns with him about alleged executions of innocent civilians in Afghanistan, as well as o…