LONDON, Sept 22 (Reuters) - Britain's third-largest sportswear retailer, JD Sports Fashion (JD.L), posted an expected 14.5 percent increase in first-half profit and said it was on track to meet expectations for the full year.

David Beckham for Adidas at JD Sports - Photo: www.jdsports.co.uk

The company, which focuses on the upper end of the sportswear market, said on Tuesday 22 September it made a profit before tax and exceptional items of 14.2 million pounds ($23 million) in the six months to Aug.1.

That compared with analysts forecasts of about 14 million pounds and 12.4 million in the 2008 period.

Revenue increased 8.4 percent to 324 million pounds and was up 0.7 percent on a like-for-like basis, while gross margin was maintained at 48.2 percent.

Like-for-like sales rose 0.8 percent in the six weeks to Sept. 12.

"With challenging conditions for the consumer continuing, the result for the full year remains very dependent on the sales and margin performance in December and January," said executive chairman Peter Cowgill. "Nevertheless, the board believes that the group is well positioned to deliver on market expectations."

Shares in JD, 57 percent of which are owned by sportswear company Pentland, have doubled in value over the past six months, outperforming other general retailers .FTASX5370 by 47 percent.

The stock closed Monday 21 September at 579 pence, valuing the business at 282 million pounds. (Reporting by James Davey; Editing by Dan Lalor) ($1 = 0.6181 pound)