All website searches using a toolbar created by broadband provider BT and Yahoo are to be undertaken by Google in the future.
In a strange development, Yahoo has lost its place on the provider's toolbar to its search engine rival.
BT and Yahoo signed a deal in 2003 to jointly market their broadband services and it is predicted the search engine could lose around 35 per cent of its search traffic to Google as a result of losing the deal.
A BT spokesman told The Register the broadband provider was "delighted" to still be working with Yahoo until 2011.
He added: "As part of this new agreement BT Yahoo's web search will be provided by Google.
"We made this decision based on the fact that Google is the most popular search engine in the UK. The combination of Google's search engine with Yahoo's leading content and email services offers customers the ultimate broadband experience."
BT recently announced it was offering new faster broadband speeds to millions of customers through its BT Broadband Accelerator.