Diane Abbott has been caught out posting a fake image of an Israeli fighter plane bombing Iran in a tweet slamming Britain's airstrikes on Syria.
Labour's shadow home secretary posted the photo-shopped image alongside a message tearing into Theresa May for not having a vote before the strike.
But when Twitter users pointed out that she was using a mocked-up image dating back to March 2012 she branded their criticism 'pathetic'.
The image was mocked up by Al Clark for The Aviationist, shows how an attack by a formation of F-15Is on a nuclear facility located in downtown Tehran might look like.
Ms Abbott posted the image with the message attacking International Development Secretary Penny Mordaunt for her interview on BBC Radio 4 Today Programme.
She wrote: 'Shocking to hear Tory minister on BBC Radio 4 Today claim that you can't allow Parliament to vote on war because that would be to "outsource the decision to people who don't have all the info".
'Do these people understand what parliamentary democracy is?'
But people on Twitter quickly pointed out that the image she had used was not a genuine photograph, but a fake image often used by the Syrian state media channel SANA TVC.
ABC reporter Julia Macfarlane wrote: 'Diane Abbott The Shadow Home Secretary here, using a photoshopped image, of what looks like an Israeli F15 jet, that has been repeatedly used on SANA TVC articles since early 2017.'
Stephen Phillips wrote on Twitter 'Clearly, Ms Abbott is incapable of discerning fact from fiction.
'Hopefully she has by now removed this scurrilous piece of #FakeNews and apologised to the Israeli government - and everyone else offended by it.
'Just as well she's more accurate with her sums.'
But Ms Abbott has refused to delete the pictured or apologise for her mistake - and instead had a go at people for critiicsing her.
She wrote: 'Apparently, my use of this pic is 'important news'. Yes, UK goes to war without U.N. approval or even parliamentary debate.
'But the most important news is what pics I use in a tweet. Pathetic.'
The row comes ahead of a hotly-anticipated parliamentary clash later today about Mrs May's decision to order airstrikes without a parliamentary vote.
The PM will deliver a passionate defence of the Syria strikes today as she faces off with MPs.
The Prime Minister will insist action to degrade Bashar Assad's chemical weapons capability was in the 'national interest' and justified on humanitarian grounds.
Pointing to the nerve agent attack in Salisbury last month, she will says it is vital that the use of such banned substances does not become 'normalised' around the world.
But Mrs May is expected to face a rough ride in the Commons, with Jeremy Corbyn branding the strikes illegal and saying military action should never be taken without U.N. - and Russian - approval.
This article has been adapted from its original source.
© Associated Newspapers Ltd.