Nearly half of primary care trusts are expecting a single commissioning consortium to span the same geographical area that they currently cover.

The finding comes from the most comprehensive analysis so far of the shape and size of the GP led groups. Previous analysis has focused on the 177 “pathfinder” consortia announced by the Department of Health.

HSJ has identified 335 emerging consortia covering a 45 million population - around 90 per cent of England - and including nearly 7,000 practices. It is based on information from 134 PCTs, mostly collected in the past two months.

Sixty-three consortia cover the same area as their PCT, although in a few of those cases a small number of practices in the area are not yet signed up.

47%:

PCT areas that match consortia

It will fuel concerns the major upheaval in the NHS could result in a similar commissioning landscape in many areas.

The average consortium population is 133,500. If this was repeated for the approximate 6 million population unaccounted for there would be an additional 45 consortia, giving a total of 380. This is higher than recent projections that there would be around 270 consortia in England.

Sources have stressed the size of consortia was likely to change significantly before April 2013, with the authorisation process almost certain to encourage larger groups.

Buckinghamshire PCT chief executive Ed Macalister-Smith said practices should be allowed to use the next two years to develop different forms and approaches. There are three well developed groups in the county.

He warned pressure on financial and performance control, and for consortia to define things like membership and governance, could hinder this.

He said: “We need to let new ideas emerge. A concern is that the innovation which is now going on in some areas could get closed down quickly because of the need to maintain grip.”

However, NHS East of EnglandGP commissioning lead Paul Zollinger-Read said consortia could remain small as long as they shared support services. He said: “[We should] expect to see consortia coming together to share functions - for example contracting [needs to be] at a much greater geographical level.”