Essex Police are being investigated by the Independent Police Complaints Commission after a driver ended up in a critical condition.

The 18-year-old, who was arrested by officers, is in intensive care, following a police chase.

Essex Police officers had mounted a pursuit along the A127 at about 3pm on September 13 after they spotted a car they believed was involved in an incident earlier that day.

They followed the car to the junction of Ardleigh Green, in Romford, where they arrested their suspect before taking him to Chelmsford police station.

About 25 minutes later, he complained about severe stomach pains and an ambulance was called. He was taken to hospital where his condition is now described as critical, but stable.

His sister has now filed a complaint with the IPCC. It will look at CCTV and also wants to trace witnesses and examine police officers’ statements.

A spokesman said: “We would be looking at all that to see if the police did everything that should be reasonably expected of them as per the guidelines to deal with these situations. It’s all about how they responded and dealt with this young man.”

The IPCC could not say where the teenager was from or where the pursuit started.

Anyone who witnessed the arrest is asked to contact the IPCC on 020 7166 3000.