* H1 revenues up an underlying 13 pct, beating forecasts

* Outlook uncertain, weakness in Spain to hit wholesale revs

* Q2 like-for-like retail sales up 2.6 pct

LONDON, Oct 14 (Reuters) - Luxury goods group Burberry beat forecasts with a 13 percent rise in first-half underlying revenues, but said trading conditions were uncertain and weakness in Spain would hit full-year wholesale revenues.

Burberry fw 08/09

The British firm, best known for its camel, red and black check, said on Tuesday it had revenues of 539 million pounds ($939 million) in the six months to Sept. 30, versus forecasts of 510 million to 529 million in a Reuters poll of 6 analysts.

Growth at constant exchange rates slowed from 22 percent in the first quarter to 8 percent in the second. This was due to earlier than normal shipments of Autumn/Winter ranges which Burberry said in July would distort its quarterly results.

However, like-for-like retail sales growth slowed to 2.6 percent in the second quarter, from 4.5 percent in the first and 6 percent in the second half of last year. (Reporting by Mark Potter; Editing by David Cowell)