Single-price discounters are expanding at a rate of 25% a year as they continue to snap up high street stores, according to a report by Him!

Poundworld may be the smallest of the ‘big three’, but it is growing the fastest, the report found. Its growth rate of 43% year-on-year is more than twice that of market leader Poundland’s 19%. 99p Stores is growing at 16% year on year.

Poundworld has more than 180 stores in the UK and plans to open 40 every year until 2017. It also has similar growth targets for its multi-priced fascia DiscountUK and its Poundworld Express stores.

Despite this growth, Poundworld is still dwarfed in terms of size and sales by Poundland, which recently reported value growth of 19.3% and like-for-like sales up 2.3% for the year ending 31 March. Poundland has over twice as many UK stores as its rival - more than 400 - and plans to hit 1,000 by 2020.

“Single price discounters are acquiring high street sites at an aggressive rate,” said a spokesman for Him! “They are enticing more shoppers into store and encouraging impulse purchases by merchandising in a varied, multi-functional fashion.”