The board of the steelmaker Arcelor has unanimously accepted an improved take over offer from industry leader Mittal Steel, according to a source close to talks in Luxembourg.Board members had been meeting to decide whether to merge with Mittal or accept a rescue plan from Russia’s Severstal. There was speculation that Mittal, the world’s number one, was raising its offer of 23.2 billion euros for Arcelor, the global number two. Now it has reportedly put forward an improved offer of 40.37 euros per share, which would value Arcelor at 25.8 billion euros. Arcelor and Mittal recently held talks to end a bitter five-month feud over the plans by Indian billionaire Lakshmi Mittal to acquire his main rival. The new company will be a global giant with an annual output of over 100 million tonnes, more than three times that of any competitor. Last month, Arcelor proposed buying Severstal, in a deal in which the Russian firm’s boss Alexei Mordashov would buy a significant minority stake in the Luxembourg group. Severstal reportedly secured a multi-billion euro loan facility from investment bank ABN AMRO.