O'Mara represented Sheffield Hallam in 2017-2019. Chosen by the Labour Party to try to take the seat previously occupied and considered a safe seat by the Liberal Democrats leader Nick Clegg, declared himself "surprised" when he was elected. A former bar manager, he had little or no political experience. In his two years in Parliament, he spoke only three times, Hansard shows.

He was ejected from the Labour Party, then readmitted, then sat as an independent following allegations of sexual harassment, staff resignations and sackings in addition to complaints from constituents, according to the BBC.

He drank to excess and used drugs, leading to what the Crown Prosecution Service described as "dire need of money."

The police investigation arose when Gareth Arnold, 30, who O'Mara had given the title "Chief of Staff," reported both O'Mara and himself - fully aware that that report would result in his own prosecution.

O'Mara claimed he was the first MP to suffer from autism and claimed to have formed a charity, "Confident About Autism South Yorkshire." No such organisation existed but it issued four invoices totalling GBP19,400 passed on by O'Mara in support of his claim for expenses. His total false claims were for about GBP52,000.

Evidence included "analysis of mobile phone records revealed references to money making schemes, bending the rules, demanding monies from IPSA, deleting records and abandoning claims for payment that might ring alarm bells" said the Crown Prosecution Service.

Jared O'Mara was found guilty of six charges of fraud and not guilty of two and sentenced to four years' imprisonment for each guilty finding, to be served concurrently.
Gareth Arnold was found guilty of three charges of fraud and not guilty of three
John Woodliff was acquitted of one charge of fraud and sentenced to 15 months' imprisonment, to run concurrently, for each guilty finding, suspended for two years