Online sales at Dixons Carphone have surged by more than 70% as Britons rushed to buy laptops, games consoles and freezers to cope with the coronavirus outbreak.

Britain’s biggest electrical and mobile phone retailer said online sales in the UK and Ireland had surged 72% in the three weeks to 21 March.

The retailer reported huge demand for home working paraphernalia such as computers and printers as well as TVs, games consoles and household appliances like fridges and freezers. Overall the retailer’s UK sales, including stores and online, were 35% higher over the short period than in 2019.

Despite the recent sales bonanza, however, the company warned annual profits were now expected to fall short of the £210m pencilled in by analysts after the government forced non-essential retailers to close their stores at the start of this week.

The group said as a result it would miss out on about £400m of sales between now and the end of its financial year in April. “There will be some recovery through online operations but overall the loss of sales will adversely impact our full-year profitability and cash position,” it said.

The store group said web sales had been very strong in all countries over the past fortnight as “people have been preparing to work from home and use essential technology to continue their lives during the coronavirus outbreak”. It added: “Early signs are that this strong trading has continued since stores closed and will help to compensate for lost store sales.”

It said it had been taking additional steps to protect colleagues who were working on web orders and that it would pay shop staff who were now unable to work. “We will stand by our colleagues throughout this crisis and, with the government’s help, we expect to keep paying those who work in our stores during these temporary closures,” the company said.

The update came as official data showed that retail sales growth had stalled before the economic shock caused by the coronavirus. Sales volumes were flat in February compared with the same month in 2019 after growth of 0.9% in January, the Office for National Statistics said. This was the first time sales have not grown since March 2013, when Britain was hit by the heaviest snowfall in 30 years.

The outlook for retailers appears bleak, especially outside the supermarket sector. Food retailers have seen a temporary surge in demand as Britons stockpiled supplies in case they are trapped at home by illness or growing restrictions on movement.

Thomas Pugh, economist at consultancy Capital Economics, said: “People should brace for an eye-watering fall in retail sales in the region of 30% month-on-month in April. Retail sales may be flat in March as exceptionally strong food sales offset weakness elsewhere.”

The ONS said that in February alone, sales dropped by 0.3% after a 1.1% jump in January, due to unusually bad weather and flooding in parts of Britain.

“A small number of retailers also said that the impact of the coronavirus had affected sales of goods shipped from China,” said ONS statistician Rhian Murphy.