The firm, which designs, sources, markets and sells own-brand clothing, shoes and accessories online to a core market of 16-24 year-old consumers in Britain and globally, said UK sales had risen 27 percent in the three months to May 31.

The rise in Britain, where Boohoo makes 64 percent of revenue, was ahead of market expectations and an improvement on growth of 13 percent in its previous quarter.

Shares in the firm, hammered after a profit warning in January, were up 3.9 percent to 27 pence at 0738 GMT on Wednesday, though still well below last year's 50p float price.

"The pick-up in UK trading is reassuring given its importance to group profitability," Investec analyst Alistair Davies said, reiterating a buy rating but holding his forecasts due to a tougher comparative trading period ahead.

Overall, total sales rose 35 percent, with international sales also up strongly as it concentrates on fewer key markets.

Boohoo maintained its full-year profit expectations.

(Reporting by Neil Maidment; editing by Sarah Young)