Carphone Warehouse has re-opened talks with Tiscali about a possible acquisition of the latter's UK broadband operations.

Carphone Warehouse, which runs the TalkTalk ISP, is reported to have made an offer of "less than £450m" for Tiscali's UK operations, in an acquisition that would make Carphone Warehouse the UK's biggest ISP.

Tiscali was put up for sale in April, and originally set June 30 as the deadline to find a buyer. However, the new offer from Carphone Warehouse, which also owns the UK arm of AOL, is believed to fall short of Tiscali's £600m asking price.

With around 1.8m customers, Tiscali is currently the UK's fourth biggest ISP.