The news came as the Smurfit board said it had agreed on the terms of Madisons 2.1bn (3.5bn) pre-conditional cash offer (PrintWeek, 10 May).

The cash offer by the Chicago-based private equity fund is 38% above Jefferson Smurfits share price on 1 May of 1.

The total offer amounts to 2.09 for each Jefferson Smurfit share, comprising 1.38 in cash and 71p for shares in Smurfit Stone Container, the groups 28%-owned paperboard and packaging firm.

The offer will allow the firms management, including chairman and chief executive Dr Michael Smurfit and European group chief executive Anthony Smurfit, to continue to run the firm.

They will also have the option to purchase up to 48m of the equity.

A spokesman for Texas Pacific Group, which is headed by Ryanair chairman David Bonderman, said the group "was not in a position to comment", but hoped to make an announcement in due course.

Story by Andy Scott