Police responding to a shoplifting call discovered what was thought to be an Uzi machine gun in the suspect’s car.
Officers had been called to Putney High Street in Putney, south-west London, at 9.50am on Thursday.
Two men had already been chased out of the shop after allegedly snatching a box containing CCTV equipment.
They then tried to climb into their getaway car parked in Burstock Road but were unable to gain access, before fleeing on foot.
Police then arrived and searched the vehicle, discovering the weapon inside.
<blockquote class="twitter-tweet" lang="en"> <p dir="ltr" lang="en">^Insp Rice - officers responding to shoplifting recovered an Uzi machine gun from suspects car - great result and hunt now on to arrest him — Wandsworth MPS (@MPSWandsworth) <a rel="nofollow" target="_blank" href="https://twitter.com/MPSWandsworth/status/639439421301985281" class="body-link" data-vars-item-name="BL-2926851-https://twitter.com/MPSWandsworth/status/639439421301985281" data-vars-event-id="c23">September 3, 2015</a>
A spokesman for Scotland Yard said: "Officers attended Burstock Road and carried out a search of the vehicle.
"They found a firearm which will now be subject to a forensic examination. Officers also recovered the stolen item close by.
"Detectives from Wandsworth CID are investigating.
"No arrest have been made and enquires continue."
