Rapid moves to merger by primary care groups may be a mistake as there is no evidence that bigger is better, according to the National Primary Care Research and Development Centre.

The literature review on the relationship between performance and size in healthcare organisations finds no evidence that increases in the size of PCGs and primary care trusts to cover more than 100,000 people will generate significant cost savings or improvements in performance.

The report also finds the optimal size will vary substantially for differing functions of PCG/Ts;

that alliances of PCG/Ts can be used to deliver the benefits of larger size where these exist; and that the relevant question is the optimal organisation of PCG/Ts, not just their size.

NPCRDC's Professor David Wilkin, one of the report authors, said they 'found no evidence to support the argument that bigger primary care groups and trusts will do better'.

NHS Alliance chair Dr Michael Dixon said: 'The larger you get, the less local accountability you have, and PCTs only work well if you keep faith with the local people.

'It would be very sad if we were just to come full circle and these PCTs were to become a revamped version of health authorities or community trusts - they must become something different, with local people directly involved in the dynamics. '