In 2021, Khan was charged under the Sexual Offences Act 2003 with having sexually assaulted a 15-year-old boy in 2008. Khan denied the accusation "in the strongest terms". On 11 April 2022, following a two week-long trial in the Southwark Crown Court, he was convicted of sexually assaulting a minor. He resigned as an MP on 3 May and was sentenced to 18 months in prison on 23 May, serving nine of these before being released in February 2023.
In his maiden speech in January 2020, Ahmad Khan spoke of being part of "a vibrant and dynamic pack of Yorkshire MPs". He called for equality of opportunity to be made real, and for more patriotism: "I see perhaps more clearly than most the deep and enduring importance of core British values such as compassion, tolerance and fairness, especially at a time when those values are perceived as under threat in many parts of our world."
Khan was part of a panel advising on grooming gangs and contributed to a paper called "Group-based child sexual exploitation characteristics of offending" while police were investigating him for child sexual abuse. Responding to the disclosures, Labour's shadow cabinet minister, Louise Haigh said, "Khan's victim told the Conservatives about sickening sexual abuse, and they did nothing, and then shamefully appointed him to sit alongside survivors of child sexual exploitation. (...) The Tories have serious questions to answer over how they gave this man free rein to exploit his position and victims of abuse. Boris Johnson and Priti Patel need to come clean about what the Conservative party knew and how they could possibly have put victims in this horrifying position in the first place." The Home Office said it was not aware of the allegations against him at the time he was on the advisory panel.
Activist Sammy Woodhouse was targeted, groomed and abused aged 14 and took part in a review with Khan. She said, "This was important work that I undertook in good faith, but I am disgusted to have been put in a position where I was working with a man later convicted for child sexual assault. Knowing now that the Conservatives had already received complaints from a victim about this man, it is gut-wrenching for me as a survivor that they could possibly have allowed him to be considered for this role."
Khan attempted to have the case heard in secrecy, first arguing that as a serving MP there were concerns about his safety and that to name him in court would breach his human rights, and attempted to have the age of his victim withheld. His applications were rejected by Chief Magistrate Paul Goldspring at Westminster Magistrates' Court, who said, in favour of open justice: "Damage to reputation is not a ground for making of an order." Ahmad Khan, an Ahmadi Muslim, applied, unsuccessfully, to have the case heard anonymously as the consumption of alcohol and homosexual acts are strictly prohibited, and reporting them could expose him to risk both in the UK and abroad.
On 10 September 2021, he pleaded not guilty at London's Old Bailey; the case was transferred to Southwark Crown Court, for trial on 21 March 2022 on a single count of sexual assault. At trial he denied accusations of dragging a 15-year-old boy upstairs, forcing the boy to drink alcohol and watch pornography, and groping the boy's groin. The complainant called police after Ahmad Khan was elected to Parliament. The complainant's older brother gave evidence that at the same party the MP had asked if he was "a true Scotsman" and lifted his kilt, before "lunging" at him. Another witness at the trial described waking to find Ahmad Khan performing a sex act on him after a party in Pakistan in 2010 where the pair had drunk whisky and smoked marijuana.
Outcome:
On 11 April 2022 he was found guilty of sexually assaulting the 15-year-old boy, contrary to section 3 of the Sexual Offences Act 2003, and jailed for 18 months on 23 May. Mr Justice Jeremy Baker said that the boy, who was particularly vulnerable, had been profoundly psychologically affected, that Khan did not regret his assault, and that he had displayed significant brutality. The victim stated that he had found it hard to be touched, and his mental health was harmed, including suicidal thoughts. Shortly after the trial Khan was accused of having offered oral sex to a 16-year-old boy at a birthday party in Suffolk in 2015, and offering to take the youth to a hotel to use cocaine and hire a sex worker.
Following his conviction for sexual assault, Khan announced on 14 April 2022 that he would be resigning as an MP. On 28 April 2022 he announced he had tendered his letter of resignation, effective from the end of April. He was to receive the entirety of his April salary upon his resignation.
His resignation was effected on 3 May 2022 following his appointment to the Chiltern Hundreds.
As a result of this a by-election was held on 23 June, in which Labour recovered the seat.
Khan was expelled from the Conservative Party following the conviction. Khan appealed against conviction and sentence, but the appeal was dismissed in December 2022. Conservative MP Crispin Blunt, chair of the Parliamentary committee on LGBTQ+ rights, defended Khan after the trial, but was criticised for his "disgraceful" comments on the conviction as a "dreadful miscarriage of justice" and "an international scandal". Several members of the committee resigned in response to his statement; Blunt subsequently apologised and withdrew his comments.
On 5 December 2022, Khan lost an appeal at the Court of Appeal. Both appeals were dismissed by three senior judges. Dismissing the conviction appeal, Mr Justice Sweeney, sitting with Dame Victoria Sharp and Mr Justice Linden, said they had “no doubt” that the trial was fair and the conviction was safe.
The hearing was also attended by the Tory MP Crispin Blunt.
Khan was released from prison on 21 February 2023, having served half of his eighteen month sentence.