The Ministry of Defence has paid out more than £100 million on legal costs and compensation linked to the war in Iraq, ministers have said.
A "large proportion" of these were over allegations brought by the now-discredited Public Interest Lawyers, added defence minister Mike Penning.
Conservative MP and former Army captain Johnny Mercer said:
"This is a complete betrayal of our men and women.
"When we should be spending money on improving the sub-standard levels of veterans' care, we have been throwing money away.
"I just find this incomprehensible."
The figures were unearthed by DUP MP Jim Shannon, who asked the Ministry of Defence what the cost of responding to vexatious legal challenges to soldiers was over the past three years.
In reply to Mr Shannon's written parliamentary question, Mr Penning said: "No precise answer is possible, since the courts do not normally make explicit findings as to whether individual cases are vexatious or not.
"We estimate, however, that the Ministry of Defence has spent over £100 million on inquiries' legal costs and compensation relating to the Iraq conflict, a large proportion of which is attributable to allegations brought by the now-discredited Public Interest Lawyers."
Public Interest Lawyers (PIL) represented complainants in the £31 million Al-Sweady inquiry into a 2004 battle in southern Iraq.
It also brought the bulk of cases investigated by the Iraq Historic Allegations Team (Ihat), which was set up with a budget of £57 million.
PIL boss Phil Shiner was struck off as a solicitor earlier this year after he was found guilty of multiple professional conduct charges.
IHAT is also due to close this summer, with its remaining cases being passed over to the Royal Navy Police.