Guy Dollé, the chief executive of steel group Arcelor, is set to perform a dramatic U-turn and throw his weight behind a merger with rival Mittal Steel, which has reportedly upped its bid to €26.4bn ($33.1bn).

Dollé, who previously favoured a deal with Russian steel company Severstal, is set to take Mittal's improved offer to the Arcelor board on Sunday, according to La Tribune.