The retail analyst says the rise in popularity of the calendar date in the UK can be attributed to the increasing influence of US culture and of retailers such as Walmart, whose Asda chain has devoted increasing amounts of shelf space to the event.
Asda has an estimated 50 per cent market share of Halloween retail sales and the retailer is offering a number of exclusive tie-ups with brand manufacturers for the seasonal products.
The 12.5 per cent increase in sales would bring sales to £315 million, up from £280 million in 2010, making Halloween the third most significant event in the retail calendar after Christmas and Easter and in front of Valentine's day.
Although the Halloween spending is set to increase, Planet Retail expects the rate of growth to slow this year as compared to a 19.1 per cent last year. This is due to the difficult economic environment.
Lisa Byfield-Green, retail analyst at Planet Retail, said: "Supermarkets such as Asda have increased their price focus on Halloween items this year and we expect more consumers to be looking for bargains in discount stores.
"Many people may look to update costumes with new accessories rather than buying new ones. We expect people to continue to spend on confectionery and party items."