Carphone Warehouse Group is tomorrow expected split the company in two, making its broadband division TalkTalk a separate business within the next 18 months. Times Online, Guardian.co.uk  and others tip CEO Charles Dunstone to break up the company he founded in 1989 – but to retain a place on the boards of both TalkTalk and Carphone Warehouse. Dunstone has been under pressure from investors to split the business after Best Buy bought a 50 percent stake in Carphone’s European business for £1.1 billion in May. TalkTalk is the UK’s third-largest ISP with 2.8 million customers, behind BT (NYSE: BT) and Virgin Media (NSDQ: VMED), with some estimates valuing the business at around £1 billion. But as with most big-money decisions in these economically troubled times, it’s unlikely any demerger could talk place for some months. Carphone reports its interim earnings on Tuesday.