Image caption Sir Howard handed over the role of chief executive to Kazuo Hirai in April

The chairman of Sony, Sir Howard Stringer, is to retire from the Japanese technology giant in June.

The Welsh-born businessman became Sony's first foreign chief executive in 2005, a post he left last year.

He presided over a difficult period for Sony, as the firm restructured and cut costs but struggled to compete with brands such as Apple and Samsung.

The 71-year-old spent 15 years at Sony, following a 30-year career at US broadcaster CBS.

Sir Howard moved to the US in the 1960s, and is a dual citizen of the UK and the US. He was knighted in 2000.

He first announced his decision to retire during a speech to the Japan Society in New York on Friday.

"A new world is opening up for me... one that allows me to complete my plan to retire from Sony, which I expect to do at the conclusion of my term later this year," he said. "That will allow me to move forward with new opportunities I've been presented with lately."

He is expected to formally stand down at an annual shareholders' meeting in June.

Record losses

In April last year, he handed over the role of chief executive to Kazuo Hirai, the long-time head of Sony's video games unit, who praised Sir Howard's "unwavering dedication and leadership".

But others have questioned his performance during a period that saw record losses at the firm, which makes flat-screen televisions, digital cameras and the PlayStation games console.

Sony has lost money for the past four years, and racked up its biggest loss in its history in the 2011-12 financial year.

Sir Howard initiated a three-year turnaround plan in 2009, promising to reform the business and bring the firm's diverse divisions closer together.

He cut thousands of jobs and put an end to unprofitable projects.

His successor as chief executive, Mr Hirai, appears to be pursuing a similar strategy, though the company's core television division remains loss-making.