PATIENTS in Swindon could have been travelling to hospital in unsafe ambulances.
The Great Western Ambulance Service NHS Trust has had to take 19 vehicles out of service because they were overloaded with too much heavy equipment and could buckle under the weight.
A spokeswoman for the trust that runs Wiltshire, Avon and Gloucestershire ambulances said: "It is down to the capabilities of the vehicles.
"The chassis can only support a certain amount of weight within a safe range.
"It is hard to say how long these 19 had been overweight for.
"The weight is always moving because we are always putting more equipment into the back.
"We weigh the vehicles by driving them onto a weigh bridge.
"The weight of the ambulances should now be 1,850kg, but 19 vehicles were 50 to 70kg over."
The ambulance service only found out about the weight problem when alerted to the problem by another ambulance trust.
Eleven vehicles were taken out of service on Tuesday evening.
A further eight ambulances will be taken off the road today.
When the trust found its vehicles could be too heavy, drivers and paramedics were sent an internal memo warning them to reduce the amount of weight they were carrying, by banning family members from riding with patients and leaving any non-essentials behind.
In the email, the trust's assistant director of operations, Keith Scott, said: "There will not be any escorts carried on the vehicle except where the patient is aged 12 or under and does not weigh in excess of 40kg.
"As a precautionary measure, vehicles should operate with the fuel tank three quarters full and the practice of carrying surplus cylinders, stock and equipment (should) cease."
So far the ambulance service has brought in nine replacement ambulances from Wales, which go into action today.
Another 14 vehicles are being drafted in from Wales and London.
Unison representative Steve Smart said: "It is crisis averted or at least delayed.
They are bringing in new vehicles or at least replacements until they can correct the weight.
"These vehicles have by and large been around for five to seven years.
"From our point of view we just didn't know about it until another ambulance service got in touch. And to be fair they did check them all quickly and take action."
Tim Lynch, chief executive of Great Western Ambulance Service NHS Trust, said: "We take the safety of our patients and staff extremely seriously.
"We will rectify any weight capacity issues with these ambulances as a priority and ensure they are fully operational as soon as possible."