Analysis of official NHS data by the TUC shows that general practice is currently operating with 9,325 GPs below the number it needs.
Based on workforce data for September 2019, there are currently more than 2,100 patients per full-time equivalent (FTE) fully-qualified GP - 31% more than than a 1,600 per patient figure cited in BMA guidance on safe working.
The south-east England region is more than 2,000 GPs short of the number it needs, the TUC estimates - after a 5% rise in patient numbers and a 4% drop in FTE GPs over the past four years.
Greater London is nearly 1,800 GPs short, north-west England needs 1,100 more GPs, and every NHS region is more than 500 GPs below the level required - apart from north-east England, which faces a shortfall of more than 400.
The latest GP workforce data show that the number of FTE GPs in England fell by 340 in the year to September 2019. Over the four-year period since September 2015, when the Conservative government promised to increase the FTE GP workforce by 5,000, the number of FTE, fully-qualified GPs has instead dropped by 1,088.
BMA GP committee chair Dr Richard Vautrey said: 'As we’ve said time and time again, there are simply not enough GPs to meet demand and guarantee safe, quality care to patients. And as doctors stretch themselves more thinly, they risk their own health and wellbeing.
'As this analysis shows, despite pledges to increase numbers by 5,000 by next year, we’ve seen the exact opposite – with hundreds fewer family doctors than we did in 2015. While election promises to boost GP numbers are necessary and encouraging, politicians must learn from mistakes of the past.
'This means both encouraging more young doctors to choose general practice, while retaining those talented and experienced GPs who work tirelessly in their communities every day. And it means tackling unsustainable workloads and mounting bureaucracy, while scrapping damaging pension rules that are causing so many doctors to reduce their hours or leave the profession altogether.'
TUC general secretary Frances O’Grady said: 'The Conservatives promised a big increase in GP numbers. But on their watch the number of doctors has fallen while demand has increased.
'Our hardworking and overstretched GPs are working tirelessly to help patients. But there are simply not enough of them to keep up with demand.
'As a result patients are not getting the treatments they need on time. And family doctors are stressed and overwhelmed. The next government must invest in our NHS and boost GP numbers.'
In manifesto pledges ahead of the 12 December general election, all parties have promised to boost GP numbers in England. The Conservatives have promised 6,000 more GPs - but has not made clear if this is an FTE figure, Labour has promised 5,000 extra FTE GPs and the Liberal Democrats have promised to 'end the GP shortage in five years.