Profits at online fashion retailer boohoo.com have almost doubled as the firm booked an increase in international sales and hailed a "momentous" year.

The group said pre-tax profits rose 97% to £30.9 million in the year to February 28, while revenue also soared 51% to £294.6 million.

Joint chief executives Mahmud Kamani and Carol Kane pointed to strong growth in the UK and the US, where Boohoo's performance "exceeded expectations".

"It has been a momentous year for us.

"The Boohoo brand has achieved outstanding revenue growth and increased profitability margins during the year. We continued to grow strongly in the UK, our largest market, whilst international growth exceeded our expectations, particularly in the USA," they said.

Sales in the US rose 140% at constant exchange rates, while in Europe they increased 50%.

Late last year, the group upped its profit outlook following bumper Black Friday trading, and then in January upgraded its full-year revenue forecasts following booming Christmas sales.

Boohoo also recently revealed plans to acquire US fashion firm Nasty Gal and rival fashion website Pretty Little Thing.

The chief executives added: "Both brands have huge potential and the acquisitions represent a step-change in the size, structure and operation of the group.

"We are confident that our expertise combined with the strength and following of our new complementary brands will greatly enhance the group's future growth and profitability."

Boohoo also said trading in the first few weeks of the current financial year has been so "promising" that it expects group revenue growth approaching 50% this year.

The retailer added that it will embark on a second extension to its Burnley warehouse, which will incorporate a "significant amount of automation".

Shares were down 3% in morning trading as investors digested the news.

Russ Mould, director at AJ Bell, said: "Investors will have noted the recent dip in retail spending in the UK which is boohoo.com's largest market and accounts for a third of its revenues."