ARM said it would keep its headquarters in Cambridge and that it would at least double the number of its staff over the next five years.

The deal will be funded by Softbank's own cash reserves and a long term loan from Japan's Mizuho Bank.Softbank is one of the world's biggest technology companies and is run by its founder, Japanese entrepreneur Masayoshi Son.It has previously acquired Vodafone's Japanese operations and the US telecoms company Sprint. The $20bn deal was the biggest foreign acquisition by a Japanese firm at the time.