Online fashion giant Asos has revealed that sales soared during the latest Covid-19 lockdown as high street stores remained closed.

Revenues at the retailer jumped 24% to £1.98 billion in the six months to the end of February, with pre-tax profits up 253% to £106.4 million.

The business said it benefited particularly from strong UK sales during the period – which covered the second English lockdown in November, the subsequent tiering and eventual third lockdown.

High street fashion rivals have been unable to open their doors throughout 2021 so far, but will be allowed to welcome back customers from next Monday.

In the UK, Asos sales were up 39% to £800.4 million, compared with 18% in the EU, 16% in the US and 16% in the rest of the world.

It said: “Overall we saw a net Covid-19 tailwind of £48.5 million – a benefit which we expect to reverse once we see restrictions lifted on the hospitality and tourism sectors.”

The integration of the Topshop brands, which Asos bought out of administration earlier this year, is also progressing to plan, the company said.

And it has remained flexible in responding to demands for “lockdown” products, as sales of formal and outfits for social events remained low.

Instead, shoppers turned to “activewear” and “casualwear” categories.

Profit margins fell during the period, however, by 200 basis points – or 2% – due to increased freight and duty costs, alongside foreign exchange rate movements going against the company.

Bosses said they hope to be in a strong position, ready to capitalise on “event-led” products, when social restrictions ease.

The company said: “We believe the shift to online retail as a result of the pandemic and the accelerating consolidation of offline retail has increased consumer confidence in shopping online.

“In the coming months we expect a portion of consumer demand will move back to stores as restrictions are eased throughout our markets, but we expect online penetration to remain structurally higher than pre Covid-19 levels.”