Charlie Croker, upon his release from prison, meets up with the widow of his friend and fellow thief Roger Beckermann, who has been killed by the Mafia in an Italian Alpine tunnel while driving a Lamborghini Miura. Mrs Beckermann gives Croker her husband’s plans for the robbery that attracted the hostile attention of his killers, which details a way to steal $4 million in gold in the city of Turin and escape to Switzerland.
Croker breaks back into the toilet of his former prison to convince the powerful crime lord Mr. Bridger, a fervent British nationalist, to finance his Italian job. Bridger, who has bribed most of the prison guards to work for him, agrees after learning that Fiat is set to build a new factory in China.
With Bridger’s backing, Croker recruits computer expert Professor Peach and a team of thieves and drivers. The plan calls for Peach to replace the programme in the computer that controls Turin’s traffic control system, creating a paralysing traffic jam that will allow the thieves to escape with the gold in three Austin Mini Cooper S getaway cars.
After planning and training, Croker, his girlfriend Lorna, and the heist crew set out for Turin. Mafia boss Altabani and his underlings are waiting in the Alps at the same pass where they killed Beckermann. Altabani warns Croker that the Mafia are aware of the gang’s intentions and smashes their getaway cars (two Jaguar E-Type and an Aston Martin DB4 drophead) off a cliff. Just as Altabani is about to give the order to shoot the gang, Croker tells him that Mr. Bridger will avenge their deaths by driving Italian-owned concerns such as pizza restaurants and ice cream parlours in selected British cities out of business. Not wanting to risk suffering on any fellow Italians, Altabani lets them go, ordering them to return to England and believing that it is too big a job for Croker to undertake. Instead, Croker proceeds with the plan, replacing the traffic control system’s magnetic tape data storage reels. On the day of the robbery, Croker sends gang member Birkinshaw, disguised as a football fan, to jam the closed circuit television cameras that monitor traffic. The substitute data reel then causes widespread traffic chaos. The gang converge on the gold convoy, overpower the guards, and tow the armoured car into the entrance hall of the Museo Egizio, where they transfer the gold to the Minis.
Altabani recognises that “If they planned this jam, they must have planned a way out.” Pursued by the Turin police, the three Minis race through the shopping arcades of the city, speed down stairs, jump between rooftops, and finally escape the traffic jams by a pre-planned route across a weir. The getaway is timed perfectly, and they throw off the police by driving through a large sewer pipe. As Mr. Bridger receives the cheers and adulation of his fellow prison inmates, the gang drive the Minis into the back of a moving customised coach. They then unload the gold and dispose of the Minis by pushing them off the mountainside.
The rest of the gang, having sneaked out of the city in a minibus while disguised as English football supporters, rendezvous with the coach in the Alps. On the looping mountain roads, driver “Big” William loses control of the coach. The back of the bus is left teetering over a cliff and the gold slides towards the rear doors. As Croker attempts to reach the gold, it slips further. The film finishes on a literal cliffhanger with Croker announcing: “Hang on a minute lads, I’ve got a great idea”.