Shareholders ignored warnings from Jan-Michiel Hessels, the acting chairman, that Fortis faced potential bankruptcy if the BNP sale did not go through. After the vote, the company said that was only a worst-case scenario.

Karel de Boeck, chief executive, is quoted as saying that the nightmare scenario for Fortis would be for BNP to walk away from the deal and the Belgian government to demand that the bank finds €6.8 billion ($8.8 billion) that it does not have to fund a special purpose vehicle for toxic assets.

At what was then the height of the merger and acquisition boom, Fortis, along with Spain’s Santander and Royal Bank of Scotland in the UK, bought Dutch banking group ABN Amro in 2007, with Fortis acquiring a private banking business as part of the deal. However, Fortis has subsequently sold off this ABN operation in what has proven to be a dramatic U-turn.