Mr Warman, who also became an assistant government whip in 2019, was sacked as minister of digital infrastructure as Prime Minister Boris Johnson put the finishing touches to his cabinet reshuffle.
Following the announcement, he tweeted: "Ministers have a huge opportunity to change our great country for the better.
"It’s been an honour to serve the government as a whip and to improve our broadband, address cyber threats and grow the digital economy.
"I look forward to doing all I can on that and more from the backbenches."
The reshuffle began on Wednesday when the PM fired both Education Secretary Gavin Williamson and Justice Secretary Robert Buckland, before replacing Foreign Secretary Dominic Raab with Liz Truss.
Yesterday, Mr Johnson confirmed which junior ministers are in or out of jobs.
Conor Burns, who resigned as a trade minister in 2020, returned to the front bench as a Northern Ireland minister.
Others moving to more high-profile ministerial roles included Alex Chalk, who was appointed Solicitor General, and Skills Minister Gillian Keegan, who now joins the Department for Health and Social Care.
Swindon MP Justin Tomlinson lost his job as minister for disabled people in the same department.
Other changes include former Brexit and Northern Ireland Minister, Robin Walker, has gone to the Department for Education, where he will work with the new Secretary of State, Nadhim Zahawi.
Helen Whately, who was the minister for social care, has been moved to the Treasury, but Jesse Norman joined the list of sackings.
Penny Mordaunt left her post as paymaster general at the Cabinet Office to become a minister at the trade department.
Nadine Dorries, best known outside Westminster for her 2012 appearance on ITV's I'm a Celebrity... Get Me Out Of Here, was promoted from being a junior health minister into her first cabinet-level job as culture secretary.
Housing Secretary Robert Jenrick was fired and replaced by Michael Gove
Treasury minister Steve Barclay replaced Mr Gove as Chancellor of the Duchy of Lancaster
Oliver Dowden moves from culture secretary to be minister without portfolio at the Cabinet Office and Conservative Party co-chair
Anne-Marie Trevelyan has been promoted to replace Ms Truss as international trade secretary
Mr Raab has moved from the Foreign Office to become justice secretary.
Victoria Atkins, MP for Louth and Horncastle, leaves her brief as Safeguarding minister and becomes Justice Minister, but retains her role Minister for the Afghan resettlement scheme and Operation Warm Welcome.
Jess Phillips MP tweeted: "As Victoria Atkins leaves her brief I want to say it's been good working together on DA Bill. On Prisons brief she has her work cut out. An example, today a man plead guilty to threatening my life while he was in prison where he is serving a sentence for threatening to kill me.