Oscar-winning actor Kevin Spacey faces potential extradition to Britain on charges of sexual assault against three men.

Britain’s Crown Prosecution Service said last week it had authorised charges against Spacey for a number of sex offences, following an investigation by police in London.

“The CPS has authorised criminal charges against Kevin Spacey, 62, for four counts of sexual assault against three men,” Rosemary Ainslie, head of the CPS Special Crime Division, said in a statement.

“The CPS has also authorised one charge of causing a person to engage in penetrative sexual activity without consent. The authority to charge follows a review of the evidence gathered by the Metropolitan Police in its investigation.”

A CPS official said Spacey would be charged if he was arrested in England or Wales.

However, The Guardian reported on Monday that – according to an official familiar with the process – Britain would seek the actor’s formal extradition if he failed to come back voluntarily.

A special unit of Britain’s Home Office, the international criminality directorate, will act on behalf of police and prosecutors. Extradition experts told the outlet that US police might soon be sent to find 62-year-old Spacey, and detain him on behalf of British authorities.

Any extradition is likely to take months to work through. First US Department of Justice officials must agree there was a probable cause the alleged offences were committed before police are ordered to detain the actor.

Only charges agreed by a US court could be brought against Spacey in Britain.

The investigation comes after London’s Old Vic theatre said in November 2017 that it had received 20 separate allegations of inappropriate conduct by Spacey from 20 men who had contact with him at the theatre, or in connection with it, between 1995 and 2013.

Spacey, once one of Hollywood’s biggest stars, was dropped from the TV show House of Cards and removed from the movie All the Money in the World after the accusations of sexual misconduct came to light.

The star, who won Oscars for best actor in American Beauty and best supporting actor in The Usual Suspects, has previously denied all accusations of misconduct.

Roberto Cavazos, an actor who worked at the Old Vic, where Spacey was artistic director between 2004 and 2015, said in 2017 he had encounters with the Hollywood star at the time “that verged on what you could call harassment”.

Just two weeks ago, it was confirmed that Spacey would star in the film 1242: Gateway To The West, his first major production since the sexual abuse allegations emerged.

He will also direct the historical drama in an international co-production with capital from Britain, Hungary and Mongolia, Hollywood media reported.

-with AAP