MPs have called for clarity about who will be responsible for commissioning ambulance services amid concerns that urgent and emergency services could become fragmented.

The public accounts committee report Transforming NHS Ambulance Services, published last week, is also critical of the variations in efficiency between ambulance services and a lack of accountability for their performance.

Committee chair Margaret Hodge said: “It is not yet clear who will commission services, who will be responsible for improving efficiency, nor which body will intervene to protect 999 services if an ambulance service gets into financial difficulty, seriously underperforms or even fails.”

In evidence to the committee, NHS chief executive Sir David Nicholson said it would be possible for ambulance services to be commissioned nationally if clinical commissioning groups asked the NHS Commissioning Board to do it on their behalf.

However, he told MPs it was more likely CCGs would band together and nominate a lead commissioner for their region, similar to primary care trusts now.

Ambulance Service Network director Jo Webber warned that commissioning ambulances at a level below the current strategic health authority regions could lead to a more fragmented service.

Ms Webber told HSJ that ambulance trusts were complaining they did not have a “clear way forward” and were concerned that commissioning expertise might be lost while it is decided who takes on the role.

She said: “We think there’s a good case for them to be commissioned at regional level at least, if not nationally… The sooner there is some guidance about what level and where this is going to be commissioned the better.”

The report also calls for a more “integrated” emergency care system to reduce ambulance handover times. A fifth of handovers take longer than 15 minutes.

Ms Webber said the new NHS 111 non-emergency phone number would be essential to join up the system and reduce pressure on ambulance services and emergency departments.