Mobile phone giant Vodafone has bought a 15 per cent stake in Japan's third largest telecommunications firm, Japan Telecom.

The £1.5 billion deal is the second-largest investment in a Japanese company by a foreign business.

Vodafone will buy stakes from two local railway firms, snapping up an 8.6 per cent holding from West Japan Railway and a 6.4 per cent stake from Central Japan Railway.

Following completion of the deal, Vodafone's stake will match those held by United States telecoms group AT&T and UK rival BT.

Another local railway firm, East Japan Railway, will remain the largest shareholder in the company, with a 15.1 per cent stake.

Vodafone already owns about 30 per cent of shares in three companies in the J-Phone Group, Japan Telecom's fast-growing mobile phone arm.