UPDATE 1-BAA halves H1 losses, passenger numbers fall

* BAA H1 pretax loss 279.7 mln stg vs 545.7 mln loss

* BAA H1 revenues 957.6 mln stg vs 937.2 mln

(Adds details)

LONDON, July 28 (Reuters) - British airport operator BAA halved its first-half losses, helped by lower one-off charges, as passenger numbers fell 4.5 percent on disruption caused by a volcanic ash cloud and strikes by British Airways BAY.L staff.

BAA, which is owned by Spain's Ferrovial FER1.MC, on Wednesday said its pretax loss narrowed to 279.7 million pounds ($434 million) as revenues climbed 2.2 percent to 957.6 million.

BAA, which owns London's Heathrow and Stansted airports, said both continued to benefit from strong retail momentum with income per passenger up 10 percent.

"Heathrow and Stansted delivered an encouraging performance during the first half of the year and this partly offset the impact of volcanic ash and the British Airways cabin crew strikes," Colin Matthews, BAA's chief executive, said.

The company took a 36 million pound hit due to the spread of ash from an erupting volcano in Iceland, which grounded much of European air traffic for a week in April.

(Reporting by Rhys Jones; Editing by Julie Crust)

($1=.6444 Pound)