Fuel price rises have seen an ambulance service spend £50,000 more on its January diesel bill than it would have paid for the same mileage last year.
Soaring fuel prices saw South Central Ambulance spend more than £351,000 on diesel last month.
The difference is the equivalent to one and a half paramedics, or a fully kitted out rapid response vehicle, South Central Ambulance said.
Last year the ambulance service's fuel bill for January was £243,000.
South Central Ambulance Service covers Hampshire, Oxfordshire, Berkshire and Buckinghamshire.
Rick Stillman, the head of fleet services, said: "We already have to make efficiency savings over the next budget year so it's putting additional pressure on the budget.
"Clearly it's one of the major ongoing costs because when we have to attend an accident or incident, you can't say we won't be there for another three hours because we've run out of fuel."
Source cheaper fuel
Mr Stillman said it was difficult for the ambulance service to reduce mileage so drivers were being urged to source fuel from cheaper outlets and avoid motorway services.
In January, last year, South Central Ambulance used 216,131 litres of diesel at a cost of £243,322 - compared to 266,502 litres at a cost of £351,045 this year.
The service has a budget of £136m for the next two financial years but has to make a saving of £5.3m.
Last month, the cost of a litre of diesel rose to more than £1.32 because of high global oil prices and the VAT hike to 20%.
With fuel costs at a record high, the UK government is facing calls to scrap a planned duty increase in April.