The breakneck pace of change means one in eight of the 8,106 practices listed in official data for April 2013 - when NHS England began - no longer appear in the latest figures from NHS Digital.
A total of 1,106 GP practices have closed or merged in the five-and-a-half-year period from April 2013 to October 2018 - more than 200 a year - while just 55 new practices have been established. NHS Digital listed just 7,055 practices in England this month.
More than 4.2m patients - 8% of the entire population registered with GP practices in April 2013 - have seen their practice close or merge since NHS England became operational.
The findings come just months after GP leaders at this year's UK LMCs conference branded the rate of practice closures in England 'a national disgrace'.
GPC chair Dr Richard Vautrey told GPonline that the rapid reduction in practice numbers reflected intense pressure on GPs.
'I suspect the majority are mergers rather than closure and dispersal,' the GPC chair said. 'But a significant proportion of the change is due to closures.'
The sharp fall in practice numbers - along with a 6% rise in patients registered with a GP - has seen the average practice list size increase by 22%, rising from 6,914 in April 2013 to 8,421 this month, the GPonline analysis shows.
Small practices were disproportionately affected - the average list size of practices that have closed or merged is just 3,838 - although practices with in excess of 25,000 patients also ceased to exist. This website revealed earlier this year that small practices are at risk despite higher average patient satisfaction.
CQC ratings show that 96% of GP practices in England are good or outstanding - but general practice is maintaining high standards under severe pressure.
A huge BMA poll last month revealed that nine out of 10 GPs believe inadequate NHS resources are undermining the quality and safety of patient care - and the profession remains more than £3bn short of the share of NHS funding its leaders say would make it sustainable.
GP numbers have slumped by 4% since former health secretary Jeremy Hunt promised to increase the workforce by 5,000 by 2020/21. With the workforce currently 20% short of the target, Mr Hunt's successor Matt Hancock recently abandoned the timescale for achieving it.
And GP workload remains at an unsustainable level - GPonline revealed last year that the profession delivers 1m appointments a week above an estimated safe limit. Meanwhile, the BMA said earlier this year that one in 10 GP practices could close by 2022 - while the RCGP has said the ageing GP workforce could drive hundreds of practices to close across the UK in the next five years.
Dr Vautrey said: 'The rapid rate of change is is a sign of the pressure GPs have been under. It has forced practices into making decisions very quickly, in some cases where they have not been able to recruit or retain GPs or other staff.'
Practices had been forced to 'collaborate in ways they were not anticipating some years ago', he said. Although in some cases this has led to 'more resilient arrangements' and has 'future proofed' groups of GPs, he warned: 'In some cases it has led to patients being left without a local service they want. That is clearly a concern.'
The GPC chair warned that moves to working at scale or in networks to improve practice resilience must not come at the expense of continuity of care.