David Tennant is to play the lead in a new ITV drama about Alexander Litvinenko, it has been announced.

The four-part drama Litvinenko will tell the story of the former Russian spy, who was murdered by poisoning on British soil in 2006, and follow the hard-working officers in the Met who attempted to find those responsible.

The casting of Tennant as Litvinenko comes after his acclaimed turn as serial killer Dennis Nilsen in Des last year. Other cast members include Mark Bonnar as detective Clive Timmons and Neil Maskell as fellow officer Brent Hyatt.

"In late 2006, Alexander Litvinenko was a living witness to his own murder," said screenwriter George Kay. "He spent his dying days entrusting the Metropolitan Police with the details of what happened to him.

"It took those police and his remarkable widow Marina Litvinenko a decade to have those claims ratified. Their stamina, hard work and bravery are what make this not only an essential story of our times but a privilege to be asked to write."

Polly Hill, ITV's head of drama, added: "After David's incredible performance as Dennis Nilsen I'm delighted he returns to ITV to play Alexander Litvinenko in the incredible story of his murder.

"George Kay's scripts are brilliant and this is an important story that documents a long police investigation and a powerful campaign for justice by his wife Marina. It is going to make a compelling drama and I am proud to have it on ITV."

Litvinenko is expected to air at some point in 2022.