More than 200 new breweries opened in the past year alone, with 1,540 now operating in Britain.
However, the 40 per cent lower costs for so-called "beerhemoths" than medium-sized producers and the vigorous acquisitive strategies of companies such as SABMiller and Anheuser-Busch InBev (AB InBev) are set to drive other brewers' products off bar and supermarket shelves.
Both companies have been keen to snap up the capital's local, independent brewers. SABMiller bought Greenwich-based Meantime Brewery in 2015 for £120m, and AB InBev acquired Camden Town Brewery for £85m in December.
Roger Protz, editor of Camra's 2016 Good Beer Guide (which is released today), said:
The way in which the global brewers are muscling in on the craft sector in Britain and other countries is a cause for concern and a potential threat to the independent sector.
In its 44-year history, the Guide has never been complacent and believes that beer drinkers’ choice and freedom demand constant vigilance.
Read more: London's craft beer mapped
Local breweries are nothing to be sniffed at - the latest research suggests the presence of a "boutique" brewery in an area of London has increased house prices by up to 105 per cent in the past five years.
The Society of Independent Brewers lashed out at big drinks firms last month, as it offered its new "Assured" stamp of approval to breweries that are “truly independent of any larger controlling brewing interest”.