Shazam, the London-based mobile music service, yesterday said that it has secured one of Silicon Valley’s most successful investors, Kleiner Perkins Caufield and Byers (KPCB) as a backer. Shazam is seeking to capitalise on the popularity in downloadable mobile phone applications. The group said that it now has 50m users, and hopes to double its customer base to 100m by the end of next year. KPCB was an early stage investor in Amazon and Google. In 1999 it bought a 20 per cent stake in Google for just $25m.