Advertising agency WPP has started the new year where it left off, by buying another firm to add to Sir Martin Sorrell's ever-expanding empire.

The firm said GroupM, WPP's global media investment management arm, had acquired a majority stake in PLAY Communication, a marketing agency based in Sydney, Australia.

Founded in 2002, PLAY offers activation, sponsorship, digital and branding services.

The company's unaudited revenues for the financial year ended 30th June 2012 were around A$4.1m, with gross assets at the same date of about A$2.8m.

In Asia Pacific, WPP now has revenues, including associates, of around US$4.7bn and employs some 46,000 people.

Its Chief Executive, Sir Martin Sorrell, recently stirred controversy by saying the amount of corporation tax companies pay is largely "a question of judgement".

In an interview with the BBC, he said companies like Google and Starbucks paid tax more out of a sense of corporate social responsibility, than because the law forces them to.

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