A committee of MPs says it has found “huge” variations in funding for clinical commissioning groups (CCGs), ranging from £137 per person below their fair share of available funding in Corby to £361 per person above their fair share in West London.

One of the government’s key policy objectives in allocating health funding is equal access for equal need, yet around two-fifths of CCGs and three-quarters of local authorities are receiving more than 5% above or below their target funding allocation, says the House of Commons Public Accounts Committee (PAC), in a new inquiry report.

And this has important implications for the sustainability of the NHS, as underfunded CCGs are more likely to be in financial deficit, the MPs warn.  Of the 20 CCGs with the tightest financial positions at March 31 2014, 19 had received less than their fair share of funding, their inquiry found.

The National Audit Office (NAO) has calculated that, at the current rate, it would take around 80 years for all local health commissioners to reach their target allocation. It would take around six years before no CCG remained below its target allocation by more than 5%. For local authorities and the expenditure on public health, this would take 10 years, said PC chair Margaret Hodge, Labour MP for Barking.

The Committee recognises that in moving only gradually from current funding levels, the priority of the Department of Health and NHS England has been to maintain the stability of local health economies. However, this very slow pace puts at risk the financial sustainability of those most underfunded, said Lady Hodge.

Moreover, the report finds that, in some areas, target funding allocations may be unreliable, because they are based on estimates of population size taken from GP registration numbers. These tends to be inflated because people can remain on lists after they have moved out of an area, while at the same time GP lists do not include unregistered patients, and this may disadvantage areas with high levels of inward migration.

The Committee also finds it “deeply concerning” that the proportion of total funding devoted to primary care has fallen from 29% to 23% over the last decade – even though NHS England had told the inquiry that primary care is expected to have more impact on reducing inequalities than CCG spending, it reports.

The MPs say they have been told by NHS England that it plans to reverse this trend and to increase the proportion of healthcare funding being spent on primary care. The agency also says it wants to bring together the budgets for CCGs and primary care, to increase local flexibility with the intention of better targeting local priorities, they add.