British Land, which owns shopping centres including Sheffield’s Meadowhall and Drake Circus in Plymouth, has had nearly £600m wiped off the value of its retail empire over six months. It also reported a bigger half-year loss due to torrid conditions in the retail industry.

The property company has written down the value of its retail investments by 10.7% to £4.8bn in its latest financial results, which cover the first half of the year. The drop comes after an 11.1% write-down in the 12 months to 31 March.

The tumbling value of British Land’s retail properties helped push the company to a loss of £440m, up from last year’s loss of £42m.

The firm said the last 18 months had been tough in the retail world as a number of large retailers had collapsed into administration or, like Debenhams and Arcadia Group, opted for insolvency procedures, known as a company voluntary arrangement (CVA), to shut stores and force through rent cuts with landlords.

Retailers are struggling because of rising costs, including business rates and the minimum wage, low levels of consumer confidence and the shift to online shopping. British Land said it expected internet shopping to continue to grow rapidly, from 19% of UK retail sales to 35-50%.

British Land shares were down 2.5% by lunchtime, at 560p. Four years ago they were changing hands at about 870p.

Chris Grigg, the firm’s chief executive, said the prospects for retailers remained grim, in particular outside London. “We expect retail to remain challenging, so we’ll focus on driving operational performance and maintaining occupancy. In London, we expect the market to remain good with supply relatively constrained, and high quality space.”

The company’s biggest asset is the Broadgate offices, retail and leisure complex in the City, and it is building a large development including 3,000 homes, as well as offices, shops and restaurants in Canada Water, on the south bank of the Thames in London just beyond Tower Bridge.

Land Securities and Intu Properties, two rivals, have also been hit by the retail downturn. Landsec, whose shopping centres include Trinity Leeds, Oxford’s Westgate, Bluewater in Kent, and One New Change near St Paul’s Cathedral, this week posted a six-month loss of £147m as the value of its total property portfolio declined by £368m to £13.4bn. Retail parks suffered the biggest decline in value, of 11.1%.

Last week, Intu, which owns the Lakeside shopping centre in Essex, blamed CVAs for a 9% drop in its like-for-like rental income.

Russ Mould, investment director at the investment company AJ Bell, said: “It is a terrible time to be a retail property investor with asset valuations still in decline and tenants asking for every bit of help they can get. British Land doesn’t believe the situation will get better any time soon.” Mould suggested the company was better placed, however, than many to benefit from changes in the way people live and work, with “a blurring of boundaries between work and leisure time – so people want to be able to socialise near to their office”.