A THIEF who stole a car from Chingford after taking the keys from a house unwittingly led police to a cannabis factory.

The lucky find took place early on January 10 after police gave chase to the stolen BMW 4x4.

The drama began when a family, up to feed their baby shortly after 2am, heard the front door of their house shut and the engine of their car revving.

The man spotted his car being driven away and immediately called the police.

Within minutes squad cars were on the tail of the BMW but couldn't keep up with the powerful vehicle.

A police helicopter with heat-seeking equipment was called out, discovered the abandoned vehicle in Leytonstone and en route noticed a hotspot in a property, leading police to uncover the cannabis factory.

The woman of the house in Chingford, who asked not to be identified said: "I was amazed after calling the police. The car was chased and found less than half an hour later.

"The police were excellent. They did a really good job. We called them and they were there straight away. Finding the factory must have been an added bonus."

The family have changed locks and stepped up security since the break-in but say they felt very reassured by the prompt police response.

DCI Derek Vickers told the Guardian: "This was an excellent piece of work by the air support unit. The tracker device in the BMW was activated and gave us the area where the car was located.

"Air support spotted the hot engine on the stationary car and it was recovered. Along the way the team pinpointed a cannabis factory using the heat-seeking gear."

DCI Vickers said that along with standard security precautions such as fitting good door and window locks and alarms, keys should not be hung in hallways or near catflaps because thieves often used fishing rods to snare them.