Britain’s military operations in Afghanistan were undermined by the threat of legal action against soldiers for possible war crimes, the former head of US forces in the Middle East, David Petraeus, has claimed. The extension of human rights laws to the battlefield made “extensive litigation against British soldiers inevitable” and threatened the long-term close relationship between the US and UK, Mr Petraeus wrote. His comments came in the foreword he wrote for a report entitled <em>Lawfare, Resisting the Judicialisation of War, </em>produced by the UK think tank Policy Exchange,<em> </em>which called for legal changes to make UK soldiers less liable to prosecution. “It is arguably as much of a threat to Britain’s fighting capacity as would be a failure to meet Nato budgetary targets and it risks putting the special relationship under increasing strain,” Mr Petraeus said. The retired general and former head of the CIA said that UK forces in Afghanistan were less able to detain enemy fighters and work with the Afghan government. He said British soldiers were increasingly subject to a different legal regime to US troops. Mr Petraeus said the “unfair pursuit” of British soldiers and veterans was of particular concern. “This is not only unfair to those who have served and sacrificed for their country, it also gravely undermines the morale of those serving now and raises an unnecessary concern for potential recruits,” he wrote. The UK government this year said it would give British armed forces stronger legal protection for “unfair” investigations into alleged crimes in Iraq and Afghanistan. Under the plans, soldiers could not be investigated for crimes in war zones 10 years after the event, other than for exceptional circumstances. The International Criminal Court said in 2017 there was a reasonable basis to suspect that UK servicemen had committed war crimes against at least 61 people in their custody in Iraq. Between 2010 and 2017, a historic allegations team for Iraq investigated more than 3,600 allegations of unlawful killings and ill treatment. British troops were found to have mistreated an Iraqi civilian who died in custody in 2003 and others were found to have tied up another detainee and suspended him from a forklift truck. But the inquiry into claims of torture, murder and mistreatment in Iraq was closed in 2017 after allegations of vexatious claims. One solicitor who brought hundreds of cases was struck off for dishonesty.