UK mobile phone retailer and telecommunications provider Carphone Warehouse has agreed to acquire Internet service provider (ISP) Tiscali’s UK broadband business for £236 million.

The deal will make Carphone Warehouse, which is preparing to divide its retail and telecommunications divisions into separate companies after entering a joint venture with US electronics retailer Best Buy, the UK’s largest broadband provider, with 4.5 million residential subscribers.

Tiscali, whose UK business customers include Tie Rack and Unwins, acquired rival Pipex for £210 million just two years ago.

In April 2009, Tiscali’s auditors, Ernst & Young, expressed concerns over the company’s future, revealing that the company owed £450 million.