A kebab seller had his generator stolen as he climbed through the serving hatch to free himself from his locked van.
The 27-year-old was working from Market Hill in Buckingham on Monday evening when he discovered he was locked in the van.
But as he clambered out through the serving hatch thieves stole his kebab van generator and made off in a car, thought to be a silver Citroen Saxo.
Police would like to speak to anyone who saw the incident which happened around 8.20pm.
There was a man nearby who spoke to the victim and police would particularly like to trace him.
If you have any information, call 101.
Alternatively, contact Crimestoppers anonymously on 0800 555 111 or online at www.crimestoppers-uk.org