Two Metropolitan Police officers are being investigated for causing death by dangerous driving after a heavily pregnant woman and her unborn child died in a crash involving an unmarked police vehicle.

The Independent Office for Police Conduct (IOPC) said the 38-year-old woman, who was fully pregnant, was killed in the collision in south-east London on October 17.

The police watchdog said two unmarked police vehicles were traveling in the Eltham area at around 6.15pm as they responded to an unrelated incident before one of the cars was involved in a crash with the woman’s vehicle on the A20, near the junction with Kidbrooke Park Road.

Lights and sirens were activated on both police vehicles according to preliminary data, the IOPC said.

In a statement, the watchdog said the officer driving the police vehicle involved in the collision and the officer driving the other police vehicle have been told they are being investigated for potential driving offences, which include causing death by dangerous driving.

The two officers who drove the police cars are also being investigated for potential serious misconduct, while a third officer – a passenger in the vehicle involved in the collision – is being investigated for potential misconduct, the watchdog added.

IOPC regional director Mel Palmer said: “The death of the woman and her baby is tragic and our thoughts are with her family and friends and all those affected.

“We have met with the woman’s family to explain our role and will provide them with regular updates as our investigation progresses.

“The woman’s family have asked that their privacy be respected at this time.

“This was a devastating incident on a busy road and our investigators are working hard to establish all the circumstances leading up to the collision and the actions of the officers involved.

“At the end of our investigation we will decide whether to refer an evidence file to the Crown Prosecution Service to consider possible criminal charges and we will also decide whether any officers should face disciplinary proceedings.”