The ambulance service is relying heavily on the goodwill and commitment of staff to keep up with the huge increase in demand over the last decade, according to Unison, which represents 20,000 ambulance workers.

The union warned that the service is suffering from staff shortages and in some areas the situation is close to being untenable.

The ambulance service is relying heavily on the goodwill and commitment of staff to keep up with the huge increase in demand over the last decade, according to Unison, which represents 20,000 ambulance workers.

The union warned that the service is suffering from staff shortages and in some areas the situation is close to being untenable.