The Ministry of Defence (MoD) is to shut down its discredited multi-million pound investigation into Iraq War veterans following a damning report by MPs.

Defence Secretary Sir Michael Fallon announced that the controversial Iraq Historic Allegations Team (IHAT) would close in the summer.

Around 20 remaining cases will be investigated by the Royal Navy Police after the probe failed to lead to any successful prosecutions. Set up in 2010, the investigation has spent £34m ($42m) of a £60m ($75m) budget originally set aside until 2019.

IHAT had taken up more than 3,500 allegations of abuse made by Iraqi civilians.

Fallon added that around 90% of misconduct cases involving British troops who served in Afghanistan are also being dropped.

The Defence Committee report said that many cases had been taken up by the team, despite some having no credible evidence.

The decision to shut the investigation comes after a public inquiry criticised the behaviour of a human rights lawyer who brought murder and abuse claims against British troops. Phil Shiner, from the now-defunct law firm Public Interest Lawyers (PIL), was struck off for misconduct after he admitted at a tribunal he had acted improperly.

"Exposing his [Mr Shiner's] dishonesty means many more claims he made can now be thrown out and the beginning of the end for IHAT," Fallon said. "This will be a relief for our soldiers who have had allegations hanging over them for too long. Now we are taking action to stop such abuse of our legal system from happening again."

On Friday 10 February, the government's Defence committee said the investigation had become a "seemingly unstoppable self-perpetuating machine" that has "proved to be deaf to the concerns of the Armed Forces, blind to their needs, and profligate with its own resources".

It said the MoD had empowered law firms to bring cases on "an industrial scale" which saw cases rise from 165 into the thousands.

"Those under investigation have suffered unacceptable stress, have had their lives put on hold, and their careers damaged," it added.

Iraq war
24 March 2004: A British soldier secures an area near a burning oil pipeline near Basra Joseph Barrak/AFP

Conservative sub-committee chairman Johnny Mercer MP, a former army captain, said: "Throughout this process there has been an almost total disregard of the welfare of soldiers and their families. We need to hold our people in the highest esteem and a repeat of IHAT must never be allowed to happen again."

The committee report said there had been a "catalogue of serious failings" in the way IHAT handled its investigations.

The report added: "IHAT investigators have impersonated police officers in order to gain access to military establishments or threaten arrest. Investigations which had previously been closed down were re-opened on the back of dubious evidence.

"IHAT has operated without any regard to its impact on the UK military, which has directly harmed their reputation across the world, and negatively affected the way this country conducts military operations and defends itself."

The MoD said they had done its "utmost" to support servicemen under investigation including funding their legal costs, providing pastoral support and tackling issues in the legal process.

Iraq war
2 July 2004: Soldiers from the The Royal Welch Fusiliers prepare to board a Chinook helicopter as they carry out patrols around Basra following several attacks on oil pipelines and facilities in the region Giles Penfound/British Army via Getty Images