FRANKFURT, MARCH 7 - Deutsche Lufthansa AG posted a net loss of 13 million euros (10.85 million pounds) in 2011, after taking a larger-than-expected charge on the sale of its British Midland unit.

A loss of 285 million euros from discontinued operations reflects current losses at British Midland Ltd. and valuation effects linked to its disposal, the German airline said in an unscheduled statement on Wednesday.

Analysts on average had expected a full-year net profit of 324 million euros, according to Thomson Reuters I/B/E/S, following a net profit of 1.1 billion euros a year earlier.

British Airways owner IAG in December agreed to buy Lufthansa's British Midland for 172.5 million pounds in the race to grab the loss-making unit's coveted runway slots at London Heathrow.

The German flagship carrier also said it would pay a dividend of 0.25 euros per share, where analysts had expected 0.47 euros on average, as an exception to its dividend policy.

This is intended to let shareholders participate in the successful operating performance in the reporting year in a way that is justifiable to the financial profile, the group said.

(Reporting by Ludwig Burger)