Market research analysts Mintel estimate that consumer spending on Halloween will rise to 320 million pounds ($418 million) this year, a 3.2 percent rise on 2016.
Millennials are responsible for much of the growth - 60 percent of that demographic spent money on Halloween in 2016.
The figures reflect a market that has rapidly expanded since the turn of the century - spending on Halloween products in the UK was just 12 million pounds in 2001, according to market research company YouGov.
This hostility has long been documented in the country's media, with newspaper columns like last week's "Call me an old witch but I hate Halloween," in London's Evening Standard being a longstanding seasonal fixture.
Experts say that many Britons' antipathy to Halloween was caused by a lack of historical attachment, as well as the view that it was an invasive cultural import from the United States.
"England hasn't been exposed to that kind of culture, the whole idea of Halloween is not only new, but their acquaintance of Halloween has not come from Scotland - it's come from the United States."
The lengthy queues building up outside some London costume emporia this year, as in recent years, attest to the event's increasing acceptance in British popular culture.
"The queues we have are ridiculous and people are happy to queue - I can't tell you the enormity of it."
Public relations manager Kyle Livingstone, at Angels to pick up a zombie costume, told Reuters that Halloween's appeal was centred on "Just fun - it's all about fun."
($1 = 0.7643 pounds)