A Walter Mitty Army enthusiast who claimed he was a war hero rewarded by the Queen for his valour has been outed as a fantasist because he is 'c**p at Photoshop'.

Dave Harper was exposed after posting a manipulated image on his Facebook page - stolen from a genuine hero soldier just given Britain's third highest medal for gallantry.

Harper crudely put his face on a picture of Lance Corporal Alfie Pope and told friends he was given a Military Cross for serving in Northern Ireland in 1969.

But the photograph of Alfie Pope was taken in 2012 and he is holding a medal for serving in Afghanistan - not Ulster - handed to him at Buckingham Palace by Prince Charles.

Bizarre: Dave Harper was exposed after posting the manipulated image on his Facebook page - yet one friend was still sucked in by the lie

Real deal: Lance Corporal Alfie Pope, whose face was replaced, during a 2012 investiture ceremony with his Military Cross - which Dave Harper, right, changed himself

Paratrooper Pope ran through a hail of Taliban bullets to save three wounded friends before being shot in the head himself - but was saved by his helmet.

Seconds later, when he came round, he got up again and ran back into the firing line again and helped the other men.

Harper was targeted by the Walter Mitty Hunters Club, a secret network of former military personnel whose mission is to expose those who fraudulently claim to have fought for their country.

Despite the terrible fake picture he produced, Mr Harper still enjoyed praise from his gullible friends who believed he was in the Parachute Regiment.

In broken English, he wrote: 'Some old photo's I found in old envelope. Most of my belongings where destroyed when my Aunts house was burned very badly. I had forgotten about them

'B****y horrible photo when I look at it, never used to wear my Beret like that normally, I look retarded'.

The terrible edit even managed to fool one of his friends and James Harmer wrote: 'You have gone up even further in my estimation.'

But his efforts to win praise for his bravery came to the attention of the Walter Mitty Hunters Club on Facebook.

The group of ex-servicemen and women will berate anybody pretending to be former serviceman.

The picture was dated October 26, 1969 - when it is thought there were no medals awarded, and also the picture would have not been in printed in colour.

Hunted down: His lie was exposed by the Walter Mitty Hunters Club, a secret network of former military personnel whose mission is to expose those who fraudulently claim to have fought for their country

Member Mark Breen said: 'That is hilarious - beret shaped with a spirit level.'

Fellow Walter Mitty hunter Mark McKendry wrote: 'A blind man could have made a better job of that photoshop.'

Steve Edward added: 'How could anyone have been fooled by that 'Photoshop' effort? You can almost see the Sellotape.'

Mitch Singleton said: 'He is wearing an Afghan medal, whilst stating this is a very old photo after a Northern Ireland tour'.

The Ministry of Defence has been contacted for a comment - as has Dave Harper.

The Facebook hit squad of military experts who out liars masquerading as SAS heroes, Falklands veterans and fake victims of post-traumatic stress

Operating anonymously, contacting each other only through Facebook, a secret network of former military personnel will secretly hunt down those who fraudulently claim to have fought for their country.

Deceptions exposed range from a fantasist SAS hero who boasted of working as Princess Diana's bodyguard to a supposed Falklands veteran and even those who falsely claim to be dealing with post-traumatic stress disorder (PTSD).

Known as the Walter Mitty Hunters Club, the small group of experts bring extensive experience from across the Armed Forces. And with a growing following of more than 45,000 people on Facebook, awareness of their work is on the rise.

Aim: The group's mission is simple - to expose those who fraudulently claim to have fought for their country

Even NHS boob scrounger Josie Cunningham has been outed by the vigilantes. She claimed she enlisted in the Royal Navy at the age of 16 and was touted as a future warfare specialist, before falling pregnant and leaving a year later. The 'hunters' have evidence which suggests otherwise.

The group's name comes from the fictional fantasist character at the heart of James Thurber’s 1941 short story. A daydreamer who longed to escape from his mundane existence, timid middle-aged accountant Walter Mitty would picture himself as a brilliant surgeon, wartime pilot and brave soldier.

But what he could scarcely have imagined was that one day he would become an everyday metaphor for those of a similar character and later adopted into British military slang.

In an interview with MailOnline, one anonymous 'Walter Mitty hunter’ said the group now gets between 20 and 30 ‘Walt’ tip-offs each weekend.

Some are ‘love rats’ who have deceived women with their alleged service history. Others do it for financial gain, boasting of their fictitious past to promote a business.

But perhaps the hardest pill to swallow for many genuine veterans is the number of Walts who are conning charities by pretending to be PTSD sufferers.

When asked about such cases, the anonymous ‘hunter’ told MailOnline: ‘We've come across quite a few who claim to have PTSD from serving in war zones by recounting stories they've heard or read about in books or from listening to real vets.

‘Then you have the worst kind. Once caught they claim PTSD, which is becoming more common, attempting to use it as an excuse and for sympathy.

‘They are not only compounding the deceit, but stigmatising a symptom that real vets find hard to admit to themselves, let alone the public.’

Named and shamed: One man caught out by the 'hunters' was Beau Plantard (left). He claimed he was an SAS hero so he could lure women into bed. The group also creates 'wanted' posters for those it exposes (right)

Fraud: Plantard even had a tattoo of Parachute Regiment-style wings emblazoned across his shoulder blade

Among the Walts exposed are a conman who pretended to raise money for a dying girl and a fantasist who claimed he was an SAS hero who worked as Princess Diana’s bodyguard.

The latter, Beau Plantard, 49, who also goes by the name John Pugh, used a web of lies to lure women into bed. He pretended he was a veteran paratrooper who had once been asked to assist with the rescue of the schoolgirls kidnapped in Nigeria by Boko Haram.

Meanwhile, Martin Heaver was jailed for six months when it came to light he had been asking people to sponsor a series of skydives to raise money for a fictitious desperately ill five-year-old girl.

The then 46-year-old posed as a war hero and even bought a paratrooper T-shirt and beret from eBay in order to give his lies more credibility.

He claimed he wanted to raise enough cash to make the girl's dying wish to meet Mickey Mouse at Walt Disney World in Florida come true. But the girl never existed and Heaver pocketed between £900 and £1,000 from around 100 unwitting members of the public.