The MP for Norwich South was seen reacting to comments from a Conservative MP during a debate on the Finance Bill on Tuesday.
He could then be seen chuckling to himself after making the gesture.
Many people took to social media to criticise Mr Lewis with some some claiming he "mocked suicide".
Cameron Bradbury said: “Just Clive Lewis being inappropriate in the Chamber whilst debating the Finance Bill…. Just a touch childish, don’t you think.”
While India Rees said: “Mocking suicide is wrong on so many levels….suicide is never a joke., especially not as a front bench MP, and v disrespectful to his fellow MP Anneliese Dodds.”
Paul Church wrote: “6,213 people died of suicide in the UK last year. It’s no laughing matter & this behaviour is ill-befitting of any MP, never mind a frontbencher. Clive Lewis should be ashamed of himself.”
However Julia Hartley-Brewer, Talk Radio's breakfast presenter, came to the MP’s defence.
She said: “Right, Clive Lewis is NOT ‘mocking suicide’, he is making a figurative joke about wanting to kill himself rather than listen to any more nonsense.
“This is not mocking anyone, it’s a joke. Everyone, calm down. Can we please stop pretending to be offended by *everything*?”
Mr Lewis has been contacted by the Standard for comment.
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