A heavily pregnant woman and her baby have died following a collision with an unmarked police car in south-east London.

The incident happened on the A20, near the junction with Kidbrooke Park Road, Eltham, at around 6.15pm on Thursday, according to the Metropolitan Police.

It is unclear whether the police car was responding to an emergency at the time, and the Met said this question will form part of its investigation.

London Ambulance Service, London Fire Brigade and London’s Air Ambulance all attended the scene.

A heavily pregnant 38-year-old woman and her unborn baby died as a result of their injuries.

This is a very dangerous road. I didn’t hear anything but when I looked out of the window I saw loads of police cars and emergency service vehicles

The next of kin have been informed, the Met said.

Detective Chief Superintendent Trevor Lawry, in charge of policing in Greenwich, said: “My heart goes out to the woman’s family and friends who have lost their loved ones in these tragic circumstances.

“An investigation into the circumstances of this collision is under way by the Independent Office for Police Conduct and we will assist with their inquiries in any way we can.

“A road closure will remain at the scene today and I am grateful for the patience of the local motorists, who will need to use alternative routes.”

Two officers who were in the unmarked car were also taken to hospital following the collision. They have since been discharged.

Residents in Eltham told the PA news agency the junction where the crash happened “is one of the most dangerous in south-east London”.

Another said: “This is a very dangerous road. I didn’t hear anything but when I looked out of the window I saw loads of police cars and emergency service vehicles.

“I saw what looked like a beige car with a dent in the side.

“The police were here for ages and the road didn’t start to open properly until Friday morning.”

Flowers have been laid at the scene of the incident.

One of the tributes laid on the road said: “My deepest thoughts are with you, your baby and your family and friends. The most awful tragedy that should never have happened and hope your family get some justice. RIP beautiful lady and your baby.”

Neighbours have suggested the incident was almost “unsurprising” given the speed at which drivers travel on the route.

One said: “They drive really recklessly and it’s a very busy road, so I see how it could happen.

“It’s very sad.”

Another resident said they had been brought to tears by news of the incident and recalled seeing “loads of emergency vehicles” throughout the night.

A spokesperson for the Independent Office for Police Conduct (IOPC) confirmed it was investigating the incident.

The spokesperson said: “We can confirm that we have started an independent investigation into the circumstances of a fatal collision involving Met Police in South East London last night (17 October).

“We were notified that an unmarked police vehicle was in collision with a member of public’s vehicle at around 6.15pm on the A20, near the junction with Kidbrooke Park Road, Eltham, SE9.

“We understand that the driver, and sole occupant, of the vehicle was a heavily pregnant woman. Ambulance and fire services attended, and she was given treatment.

“The woman and her baby sadly both died.

“We sent investigators to the scene and post-incident process to begin gathering evidence. Our investigation is in the very early stages.

“Our thoughts are with the family and friends of the woman who has died and all of those affected by this tragic incident.”