Mr. Durkan wrote to the minister after it was revealed that a woman injured in a three-car crash in Eglinton had to wait 45 minutes for an ambulance.

An ambulance was tasked to tend to the woman but was stood down and another vehicle was diverted from Toome, on its way back from Belfast, and took 45 minutes to arrive.

"This merits urgent investigation by the Ambulance Service," Mr. Durkan said."The combined effect of this shocking episode along with the two breakdowns by an ambulance in September will lead people to question the fitness for purpose of existing ambulance services serving the North West."

He added: "While news of significant investment in the ambulance fleet is welcome, its benefits will not hit our roads for some time.

"I have therefore asked the Minister to meet with me as a matter of urgency in order to establish what measures he is taking to ensure confidence in and effective delivery of ambulance services in Derry and its surrounding area."