Customers searching on Apple's Safari browser across its Mac, iPad and iPhone portfolio already received Google search results, and investment firm Bernstein has estimated Google currently pays around $3bn (£2.2bn) for this deal, based on the fact Google paid around $1bn for the same deal in 2014.  

However, from Monday, Google will also act as the web provider for Siri as well as being the default provider for the 'Spotlight' function on Apple devices. The switch was first reported by TechCrunch.

The iPhone maker said it decided to switch its default search provider to "allow these services to have a consistent web search experience with the default in Safari". 

However, the spokesman added: “We have strong relationships with Google and Microsoft and remain committed to delivering the best user experience possible.”

Google did not respond to requests for comment.