Google agreed to pay up to $1.2bn (£700m) to break into radio advertising yesterday as part of the internet search giant’s offensive on the traditional advertising world. Google will initially pay $102m in cash for dMarc Broadcasting, a privately held American company which runs a digital platform for selling, scheduling, delivering and tracking radio advertising airtime.

Depending on the success of dMarc’s integration into Google’s existing advertising sales platform, called AdWords, Google might pay an additional $1.14bn over three years, potentially making the deal worth more than it paid last month for a stake in AOL.

The acquisition is the latest offensive by Google, the world’s largest internet search engine, to diversify its business into other parts of the advertising market.

By Katherine Griffiths in New York