An ambulance answering an emergency call was delayed at the barrier of Britain's only toll motorway after the paramedic driver was asked to pay £3, it emerged today.

The driver was only allowed through the barrier after switching on the vehicle's blue flashing light, Staffordshire ambulance service claimed this morning.

The ambulance service is now seeking urgent talks with Midland Expressway Ltd, the company which controls the M6 toll booths, to ensure that emergency vehicles are never held up at exit barriers again.

An ambulance service spokesman said: "You had the farcical situation of an emergency vehicle - with its blue lights flashing - sitting at a barrier because they wouldn't raise it."

The emergency vehicle was held up "for some minutes" at 9.20pm last night as it drove towards Lichfield to provide emergency cover. The toll booth operator refused to give the Vauxhall Astra estate free use of the motorway because it did not have the word "ambulance" on its side, the ambulance service claimed.

The driver received an emergency call while at the toll exit and the barrier was not raised immediately even when he explained that the situation could potentially threaten lives, according to the ambulance service.

The spokesman added: "The car was clearly marked up with a green-and-white checked stripe down each side and the Star of Life on the bonnet. On each door is the crown badge and there are blue lights on the grille and a blue light bar across the roof." Life-saving equipment was also clearly visible inside the car.

The managing director of Midland Expressway Ltd, Tom Fanning, said all "properly liveried" vehicles, that is where the word "ambulance" appears on both sides of the vehicle, are automatically given free access.

He said: "Ambulances that are not clearly liveried are allowed through provided that the ambulance service control room telephones ahead to give us advanced warning so that we can give it free and unhindered access. In this case no advanced notice was given but the vehicle was let through after discussion at the barrier."