In the retail analyst's UK Value Clothing Retailer 2007 report, it is predicted that Primark's share of the value clothing market will rise from 14.3% in 2006 to 18.4% by the end of this year.
According to Verdict, George at Asda, the brand that kick started the value clothing trend when it launched in 1990, will fall behind Primark, with Tesco, New Look and TK Maxx next in line.
Primark opened a flagship store in central London last spring and has increased its square footage by a massive 70% over the last 18 months.
Maureen Hinton, lead analyst for Verdict Research, said: ''Primark owes its success first and foremost to its investment in property. The clothes are still cheap but the stores themselves don’t look so and are in prime locations.''
The stores also have the advantage of "youth appeal", attracting those customers who have a greater amount of income available to spend on clothing.
Hilton said: ''Most value retailers, such as George, attract more of a family shopper whereas Primark's market is much younger. The family shopper might have more disposable income but a large proportion of it has to be spent on household goods, such as mortgage and food, whereas younger customers don't tend to have to worry about those things.''
In 2007 the value clothing market is set to reach sales of £8.5bn and will account for a quarter of all clothes bought in the UK this year.
However, as more mid-range clothing retailers such as Marks and Spencer and Next lower their prices to compete, the growth rate of the value market is starting to stall. Hilton adds: ''This trend heralds a new cycle where retailers must work harder to inspire people to buy.''
Picture: Primark's new 70,000sq ft Oxford Street store