Halloween is now the third largest retail season after Christmas and Easter, with Brits likely to pay out £315-325 million on costumes, confectionary and pumpkins, according to Planet Retail.
The influence of the US and the availability of a wider variety of spooky-themed products have contributed to a steady rise in Halloween spending over the last decade, according to the analysts.
Brits paid just £12 million for Halloween goodies in 2001. This year's estimate is significantly up on the 2012 figure of £285 million.
Sophie Carroll, associate analyst at Planet Retail, said: "This rise reflects a more favorable economic climate, as well as an increased Halloween focus on the part of retailers, with competitive in-store prices on associated products and accessories.
"Though now established as a significant UK retail season in its own right, the British passion for Halloween remains fueled by US cultural influences, with the popularity of TV shows such as The Walking Dead and the Twilight movie franchise inspiring interest in the festival from across all ages."
Independent costume hire store Angels Fancy Dress said it now employs security guards at its London shop in the run up to Halloween, such is the demand for novelty wear.
Director Emma Angel said: "Every year, Halloween gets bigger, both in terms of the money that people spend, and the effort they go to with costumes.
"It has now reached a point where we have to employ security guards and operate a one-in-one-out policy at our Shaftesbury Avenue store during the week of Halloween.
"At times the size of the queue has meant that people have to wait up to 2 hours to get access to the store. Currently, our online orders across the UK are up 50% on the same period in 2012.
"The Americans might have popularised Halloween as a retail phenomenon, but when it comes to inventive and humorous costumes, no one beats the British."
The book industry is also cashing in in the run up to Halloween, with publishers Bloomsbury re-releasing the works of Dennis Wheatley, renowned for his occult novel The Devil Rides Out.
Wheatley (1897-1977) was one of the world's best-selling authors during his lifetime and Bloomsbury hopes to find a new generation of readers with the release of titles including The Forbidden Territory and The Devil Rides Out in e-book form.
Stephanie Duncan, digital media director at Bloomsbury Publishing, said: "Last week's 'Super Thursday', the annual day when key Christmas titles are launched, now coincides with the pre-Halloween retail rush, and therefore represents a double opportunity for Dennis Wheatley and similar authors.
"Halloween has moved from being just about pumpkins and trick or treating into a much broader social trend, influencing every aspect of retail, with e-books becoming the latest sector to benefit from the general public's October appetite for the spine-tingling and the macabre."