One worker said she thought a “bomb had gone off” after there was a loud explosion in Ilford High Road this afternoon.

The explosion was from the underside of a fire engine which had just left Ilford fire station at about 2.30pm. A fire officer said it was believed to be from a gas cylinder stored in the engine.

Nurma Khanum, 19, a receptionist at the Ilford Recorder’s office nearby, said: “I was on the phone and I didn’t know what to do, I just hung up the phone. I thought a bomb had gone off. It shook the whole building.”

Opposite the fire station staff in the RGB electronics shop ducked for cover on hearing the explosion.

Manager Jaz Bansal said: “I was doing some work and then heard the bang and I just jumped up and a few of my colleagues were ducking.

“A fireman explained it was the breathing apparatus which had exploded.

“I thought it could be a bomb, you don’t know nowdays.”

Watch Commander Pat Hegarty said it was still unclear what had happened and there would be an investigation.

The fire engine was moved to the forecourt of the station and then towed away.

Mr Hegarty said the engine and its crew was on the way to fit smoke alarms in homes.