Esat chairman Mr Denis O'Brien resigned suddenly yesterday, taking executives at its parent group BT by surprise. Mr O'Brien, who founded Esat and gained more than £230 million (€292 million) when it was sold to BT for £1.9 billion last January, claimed his relationship with the parent group was "fantastic".

While the British group originally asked him to stay on as chairman for two years, Mr O'Brien said he was happy to leave now because the integration of Esat, its mobile phone company Digifone and Internet arm Ocean was complete. The group will be relaunched shortly by its chief executive, Mr Neil Parkinson. Mr O'Brien will concentrate on developing telecom businesses in the Caribbean, the Netherlands and Italy following his departure from Esat.