LONDON, April 12 (Reuters) - Apple on Friday lost a bid to throw out a mass lawsuit valued at just under $1 billion brought in London on behalf of more than 1,500 app developers over its App Store fees.

The case, worth up to 785 million pounds ($979 million) and one of several faced by the tech giant in the United Kingdom, alleges Apple charged third-party developers unfair commissions of up to 30% on purchases of apps or other content.

Apple's lawyers argued developers cannot have a claim in the UK unless they were charged on purchases made through the UK App Store. But the company's bid to throw out that part of the case was rejected by the Competition Appeal Tribunal on Friday. (Reporting by Sam Tobin; editing by Sarah Young)