A national review of PMS contracts by NHS England found that PMS practices receive £325m in funding over and above GMS core pay.
Once the redistribution of MPIG top-ups to core pay - which starts from April - is complete, this funding 'premium' received by PMS practices will drop to £235m.
Area teams have been told that they must move to a position where all practices 'receive the same core funding for providing the core services expected of all GP practices'.
A letter sent to area teams on Monday by NHS England gives the local NHS organisations two years from 1 April 2014 to complete local PMS contract reviews, and to decide 'how far to redeploy any premium funding and on the pace at which redeployment takes place'.
GP leaders reacted angrily to the move.
GPC chairman Dr Chaand Nagpaul said: 'The BMA believes that removing a pot of PMS resources from core GP budgets, worth £235 million, will exacerbate pressure on GP practices. This money, should instead have been directed into core GP practice funding across the profession.'
He warned stripping this funding from practices struggling with an ageing population with more long-term conditions 'does not make any sense'.
Dr Nagpaul added: 'This uncertainty, coupled with local negotiations between PMS practices and with area teams, will further undermine GPs' ability to make long-term decisions about how they plan patient services for the future.'
GPC deputy chairman Dr Richard Vautrey told GP: 'NHS England had a golden opportunity with this review to invest in core general practice in order that practices could plan for the future with confidence and invest in GPs and other staff to meet the core needs of their patients, not least in offering enough appointments.
'Instead they are taking a massive amount of funding away that will cause huge concern to PMS practices, with the expectation that they can only earn some of it back if they do even more work. At a time when practices are being crushed by massive workload, and GP recruitment and retention is reaching a crisis point, this is the last thing they wanted to hear.
'It is also a loss to GMS practices who may have vainly hoped that the value of global sum could have been increased using some of the PMS investment. This would have helped all practices, both GMS and PMS. Instead it means that large numbers of GMS practices with high correction factors will also lose out. All practices will be faced with difficult decisions about the sustainability of the services they offer. NHS England had an opportunity to resolve many of the problems facing practices but their failure to do this suggests they still do not fully understand the needs of general practice and the patients we serve.'
NHS England's review began with a calculation of total expenditure on PMS practices. It then identified elements of PMS expenditure 'comparable with payments to GMS practices', and then calculated the difference between this and the weighted capitation funds they would receive if they were on GMS deals.
Data collected from area teams showed that PMS practices receive £325m, or £13.52 per weighted patient, in excess of the GMS equivalent.
Just £67m of this funding was found to be linked to 'defined enhanced services or key performance indicators', although the report said the 'remaining £258m may be associated with enhanced services or populations with special needs, but is not defined'.
The NHS England letter makes clear that area teams should 'provide a manageable pace of change' for practices. But GPs warned that many practices could be severely destabilised by cuts in funding and some demanded a transition period in line with the seven-year MPIG redistribution.
Ben Dyson, director of Commissioning Policy and Primary Care at NHS England, said: 'NHS England is committed to supporting innovation and quality improvement in primary care and reducing health inequalities.
'We want to continue to use PMS arrangements to achieve these objectives. At the same time, we need to ensure that there is an equitable approach to funding. Where GP practices are receiving extra funding per patient, this has to be fairly and transparently linked to the quality of care they provide for patients or the particular needs of the local population that they serve.
'The purpose of this review has been to put in place a much clearer framework that will enable our area teams to ensure that extra investment in PMS meets these criteria.'
- Click here to read the NHS England letter in full
- Viewpoint: BMA deputy chairman Dr Kailash Chand: Why government health reforms make GPs the administrators of NHS cuts
- How PMS practices will be affected financially by the NHS England review