The police watchdog Sir Tom Winsor is challenging the former editor of the Daily Mail in the controversial race to become chairman of Ofcom, The Daily Telegraph can reveal.

Sir Tom, Her Majesty’s Chief Inspector of Constabulary, was among four candidates interviewed for the role by a specially appointed panel on Friday, media sources said.

His candidacy pits him against Paul Dacre, who led the Daily Mail for 26 years until he stepped down in 2018.

Sir Tom, a 62-year-old lawyer, is a respected regulatory veteran, having previously served as Britain’s Rail Regulator until the position was abolished in 2004 reforms following the collapsed of Railtrack.

After years as a partner at the law firm White & Case, in 2012 home secretary Theresa May appointed him the first police watchdog without a background in policing.

Supporters said Sir Tom’s experience in the nine years since would be invaluable in Ofcom’s forthcoming role in regulating online harms such as harassment and extremist material.

The watchdog will gain oversight of Google and Facebook, alongside its existing responsibilities on broadband, the BBC and Royal Mail.

Mr Dacre, 72, was first linked with Ofcom last summer and is said to be the Prime Minister’s preferred choice to run the media watchdog, as part of an effort to install conservative figures in culturally influential positions.

Downing Street last year sought an Ofcom chief executive with a commercial background, but ultimately agreed to the more conventional appointment of a senior civil servant, Dame Melanie Dawes.

Whitehall sources said Mr Dacre has been in discussions with officials about how to guard against potential conflicts of interest arising from his shareholding in the publisher of the Daily Mail, as well as other investments.

The former culture minister Lord Vaizey was also interviewed last week. He stepped down as an MP at the last General Election and has built up a portfolio of jobs related to the media and telecoms industries, including as an adviser to a specialist investment bank.

Maggie Carver, Ofcom’s deputy chairman and a former investment banker, was also interviewed for the top job on the board. She is currently covering the role following the retirement of Lord Burns last year.

The chairman of Ofcom is appointed by the culture secretary, Oliver Dowden following scrutiny that includes Lord Livingston, the former chief executive of BT.

The Department for Culture declined to comment. Sir Tom could not be reached.