Online fashion retailer Boohoo saw sales soar during the lockdowns of 2020, with a 40% increase in revenue in the time of the coronavirus pandemic.

The increase in sales – which comes a day after fellow internet retailer Asos reported a 23% increase in sales during 2020 – comes as the Manchester company is under scrutiny for working practices in some of the factories that supply it.

Boohoo said that its Agenda for Change programme set up to tackle those criticisms was making 'significant progress'.

The company reported a 42% increase in sales over the 10 months up to the end of 2020, with particularly strong growth in America. Revenue over that period stood at £1.47bn.

Sales over the last four months of 2020 were up 40%, and the company said it expected revenue growth for its current year to be around 36%, ahead of previous guidance.

CEO John Lyttle added: “I'm delighted with the group's performance over the peak trading period.

“Our team worked exceptionally hard in 2020 as we navigated the many challenges, including the COVID-19 pandemic and the successful acquisition and integration of Oasis and Warehouse. Growth has been strong across our multi-brand platform and we have continued to grow our market share across all geographies.

“I'm pleased to be able to provide a further update on our Agenda for Change programme today, which demonstrates our ongoing commitment to transparency as we invest in our approach to sustainability and our supply chain for the benefit of all of the group's stakeholders.

“The group is in an excellent position entering 2021, which we expect to be another year of progress towards our goal of leading the fashion e-commerce market globally."

Boohoo's rapid growth has been overshadowed in the last few months by allegations of poor working practices at some of its suppliers in Leicester and abroad.

An independent review of the claims found that although Boohoo did not intentionally profit from the poor working practices, but the firm's monitoring of some suppliers was 'inadequate".

That report led to the company's Agenda for Change programme, which is focused on raising standards in its supply chains and supporting workers' rights in Leicester, among other matters.

A report by former High Court judge Sir Brian Leveson said that Boohoo was making progress in those areas but noted that it was a “work in progress".

Boohoo's executive chairman Mahmud Kamani said: "I'm pleased to publish Sir Brian Leveson's first report today. I'm immensely proud of the speed with which our team has worked to effect change during such a challenging period for the group, and it's encouraging to see our progress acknowledged in the report.

“We've added further independent experience to the board and its committees in the period, and I was delighted to welcome Shaun McCabe to the board in November.

“I'd like to take this opportunity to thank our team for their exceptional hard work over the last few months, and to reinforce our commitment to being a leader for positive change in UK textiles manufacturing. We have lots to do still, but an exciting year lies ahead for boohoo and our multi-brand platform in 2021."