Collins Stewart Tullett, the UK financial services group, will have to tread carefully to ensure rival interdealer broker, Icap, does not end up as the greatest beneficiary of its takeover of Prebon.

The Tullett Liberty merger with Prebon is expected to result in pre-tax savings of about £60m a year when the £125m (€182m) acquisition has been integrated. This will make a valuable contribution to the bottom line but, before then, integration costs are likely to hit £80m.