London, UK - Britain's biggest retailer Tesco said it saw no let up in sight as it posted a 6 percent fall in annual profit, its second straight year of decline, piling pressure on Chief Executive Phil Clarke.

The group, the world's No.3 retailer, showed trading had deteriorated throughout the 12 months, with the key figure of sales at its British stores open over a year, excluding fuel and VAT sales tax, down 3 percent in the fourth quarter, its worst drop in Clarke's three-year tenure.

"Our results today reflect the challenges we face in a trading environment which is changing more rapidly than ever before," he said on Wednesday. "Competition has intensified, particularly at home."

The darling of the retail sector during two decades of uninterrupted earnings growth, Tesco has suffered in recent years from failed attempts to break into the United States and Japan, a costly expansion in China and fierce competition at home.

The 95-year-old retailer stunned the industry in 2012 when it warned on profits for the first time in two decades. Two years on, and despite Clarke spending billions on improving services and stores, Tesco's core UK market share has slipped to a near 10-year low.

In common with the UK's three other leading grocers - Wal-Mart's Asda, Sainsbury's and Morrisons - Tesco has been squeezed between hard discounters Aldi and Lidl and upmarket grocers Waitrose and Marks & Spencer.

It said trading profit for the year to February 22 was 3.3 billion pounds ($5.52 billion), in line with forecasts but down on a restated figure of 3.52 billion posted in 2012-13. The dividend was maintained at 14.76 pence a share.

Its fourth quarter sales decline compared to a 3.1 percent fall at Sainsbury's and comes as the UK grocery market is growing at its slowest rate since 2005 due to falling food price inflation and a lack of consumer spending.

Overseas, group trading profit was down 5.6 in Asia and down 28 percent in Europe, where trading has slumped in its markets of the Czech Republic, Hungary, Poland, Slovakia and Turkey as well as Ireland.

The group wrote down the value of its European assets by 734 million pounds and took a charge of 540 million pounds on its Chinese business.

Tesco's fightback has forced the firm to cut prices and abandon an industry-leading target for operating margin in Britain, but problems continue to mount up, the latest being this month's resignation of finance chief Laurie McIlwee, which has raised questions over Tesco's management and direction.

Shares in Tesco, which makes over 60 percent of sales in its home market, closed at near 10-year lows of 286.30 pence on Tuesday, valuing the business at 23 billion pounds.