'Two traffic officers noticed the driver of a car using his mobile phone on the A40 in Perivale at about 9.45pm on Saturday.
'They attempted to get the driver of the vehicle to pull over. The driver of the vehicle refused and drove into Lily Gardens, Perivale, where he made off from the vehicle on foot.
'The two traffic officers chased after the man. After a short distance, the man fired a shot at the officers.