The number of problem drinkers has almost doubled since just before the start of lockdown, figures analysed by the Royal College of Psychiatrists show.
Public Health England data showed the prevalence at almost a fifth (19 per cent) in June, up from 10.8 per cent in February. Using Office for National Statistics population estimates, the college said June's figure equated to more than 8.4 million people, a rise from around 4.8 million four months earlier.
The Government must commit to "substantial" investment in public health to prevent more lives being "needlessly lost" to addiction, said Dr Adrian James, the college's president.
A college report, published on Tuesday, urges the Government to reverse cuts and help local authorities work towards investing £374 million into adult services to address increased need.
The organisation said the steep rise in higher risk drinking came alongside a rise in people seeking help for opiate addiction. Figures show new adult cases in April up by around a fifth on the same time last year and at their highest level since 2015.
It warns that cuts to addiction services since 2013-14 could mean people missing out on life-saving treatment.
Dr James said services had been "starved of funding in recent years" and that "more lives will be needlessly lost to addiction unless the Government acts now and commits to substantial investment in public health, including adult addiction services".
Prof Julia Sinclair, the college's addictions faculty chairman, said: "Drug-related deaths and alcohol-related hospital admissions were already at all-time highs before Covid-19. Unless the Government acts quickly we will see these numbers rise exponentially."