Debenhams say they have begun stocking the 5XL size in male ranges to meet the rising need for larger clothes around the country, after being inundated with requests for bigger items.
The new big and tall range with clothes in 5XL have up to a 64-inch chest and a 20-inch collar.
Previously their stock stopped at 3XL, but demand for larger sizes of shirts, suits, tops, casual jackets and trousers had soared by 170 per cent in the last two years.
A spokesman for the fashion retailer said one in nine of all menswear purchases in its stores nationally are now larger than size 2XL, which is 50 to 52 inch chest and 18 inch collar.
Tim Pulman, Crawley store manager in County Mall, West Sussex, said: “We recognise that men from across Crawley are in general taller and stronger than previous generations and there is growing demand for mainstream men’s fashion in larger sizes.
“Our expanded range with more items in longer lengths, bigger chests and waist sizes is keeping pace with those changes.
“We believe that offering diverse and quality products means we can satisfy a greater number of our customers and we are delighted to be able to offer fashion to fit all.”
Retail analyst Columino said last year the UK spent £2.1 billion on XL garments, a rise of £200 million from four years ago, and predicts an increase by another £200 million in just the next 24 months.