In the 2019 Conservative Party leadership election, Duncan Smith served as chairman for Boris Johnson's leadership campaign, resulting in an emphatic win, with over 50% of MPs and 66% of the Conservative membership voting for Johnson to become the next Leader of the Conservative Party and Prime Minister. He was knighted in the 2020 New Year Honours, for political and public service. The honour sparked criticism, with more than 237,000 people signing an online petition, set up by Labour Party activist Dr Mona Kamal Ahmed, an NHS psychiatrist, demanding that it be rescinded.