The fire, which took place just off The Square, started at 2am this morning.
Fire crews from Bishop’s Waltham, Botley and Wickham battled to get the blaze under control.
No one was injured but severe damage was caused to a neighbouring building occupied by structural and civil engineering consultancy Arch Associates, Hampshire Fire and Rescue Service confirmed.
Patricia Mitchell, from Arch Associates, said: ‘I don’t know exactly what happened but it is just terrible. We have lots of drawings and computers in the building.
‘At the moment we cannot go in there as it is unsafe. Apparently upstairs is bad. I thought someone had just broken in when I got here and saw the front door this morning, but it is worse than that.’
Neighbour Paula Locke, who lives in Brook Street, said: ‘I didn’t hear anything. I usually pass by here and say hello to the kebab van owner, he is a really nice man. I can’t believe the devastation. It is unbelievable.’
Another neighbour Janet Locke, also of Brook Street, said: ‘Dear oh dear, it has done a lot of damage to the van and the building, and inside the building. It is a good job that I didn’t hear anything at the time as I am a terrible worrier. I just can’t believe it happened so close to me.’
The fire was put out just before 5am. It was not known how the fire started, however police are investigating.
A police spokeswoman said: ‘Police are investigating the cause of a fire in Bishop’s Waltham.
‘The incident happened during the early hours of Tuesday, May 7. Hampshire Fire and Rescue Service attended The Square to put out a fire in a burger/kebab van.
‘The matter is under investigation. Anyone with information should call police on 101 quoting 44190156139.’