Sony is to buy Ericsson’s 50 per cent stake in its joint mobile phone venture for just over 1 billion in cash, it was announced yesterday.

Sony Ericsson will become a wholly owned subsidiary of Sony, giving the electronics firm ownership of vital patents and a broad intellectual property cross-licensing agreement covering Sony products and services.

Sony said the deal was “a logical strategic step” that took into account the shift in focus of the mobile market from simple handsets to smartphones with access to rich content.

The deal is expected to close in January.