Analysis of data from NHS Digital by GPonline show that in June 2017 there were 7,435 GP practices, compared with 8,106 listed in June 2013 - a drop of 671.
The average practice list size in June 2017 was 7,860, compared with 6,967 four years earlier, the data show.
In data for June 2013 - the first on practice list sizes published after NHS England was established in April that year - just nine CCGs had average practice list sizes in excess of 10,000 patients. In June 2017, however, 37 CCGs - around one in six of the total number in England - had average practice list sizes greater than 10,000 patients.
GP list size
The statistics on patient populations registered with GP practices also reveal a sharp rise in numbers of patients aged over 85 - the group in which consultation rates are the highest. In June 2013, there were around 1.24m patients in this age group, compared with 1.35m in June 2017.
The data on numbers of GP practices do not make clear what proportion of the reduction in practice numbers is caused by mergers, and what proportion resulted from closures. But GP leaders have made clear that practice closures are at record levels.
GPonline reported earlier this year that 3% of practices had closed or merged in the 15 months to April 2017. This website also reported in November 2016 that one in 10 GPs believed their practice was at risk of closure in the next year because of underfunding, recruitment or workload issues.
GPC deputy chair Dr Richard Vautrey said: 'There is clearly a year-on-year rise in the average size of practices, but that only tells part of the story. Clearly in some cases practices have merged and joined, while in others they have closed due to workload or resource pressures or both.
Economies of scale
'Bigger practices, while potentially benefitting to an extent from economies of scale, don't necessarily solve problems with resources or recruitment.
'With the population getting older and needing to see the GP practice team more, the spiral of workload and demand is not solved by making practices bigger - we need to expand the workforce in relation to the population to provide more appointments.'
Dr Vautrey said it was harder for larger practices to maintain continuity of care, but it 'can be done'. He said: 'They have to work to remain connected to the community they serve - that has been a success of general practice over the years and is important to maintain.'
He added: 'One of the real challenges is, how do you accomodate a larger practice team - even if practices have the resources to employ more staff - when funding to expand premises remains limited?'
A DH spokeswoman said last week: 'GPs are the absolute bedrock of the health service which is why this Government has made a real-terms investment of £2.4bn into the sector - helping to cut red tape, paying some of GPs' high insurance costs and delivering innovative new schemes to retain more GPs.'