A man has been arrested on suspicion of the murders of ex-EastEnders actress Sian Blake and her two children, police said.

Arthur Simpson-Kent, 48, was detained by Metropolitan Police officers at Heathrow Airport after arriving on a flight from Ghana. He has been taken to a west London police station.

Sian and her sons Zachary, eight, and four-year-old Amon vanished on December 13 and were found buried in the garden of their family home in Erith, Kent, on January 5.

Sian Blake
Sian was suffering from motor neurone disease before her death (Metropolitan Police/PA)

Simpson-Kent, Sian’s boyfriend, was returned to the UK after agreeing to be extradited from the African country.

The hairdresser left the country days after the trio were reported missing.

Scotland Yard is under investigation by the police watchdog for the way it handled the missing persons inquiry and why it took more than three weeks to find the bodies of Sian and her sons.

The back garden of the house was only thoroughly searched in early January after murder squad detectives were called in.

The Eastenders actress' sister and mother, Ava and Pansy Blake
The Eastenders actress’s sister and mother, Ava and Pansy Blake (Yui Mok/PA)

Sian played Frankie Pierre in 56 episodes of EastEnders between 1996 and 1997.