The donation is equivalent to the amount given by the Science Minister, Lord Sainsbury.
The 55-year old Mittal, chairman and chief executive of Mittal Steel Company, the world's largest steel producer, which has operations in 14 countries across four continents, said he was making the donation as he supported the government's "long-term investment plans to further improve education, health, employment, skills and technology."
Three years ago he was at the centre of a controversy about Labour's links with business after it emerged that Blair had supported Mittal's bid for Sidex, the Romanian state steel company, two months after the businessman had made a donation of £125,000 pounds to the Labour Party.
Mittal is ranked the 54th richest man in the world by Forbes magazine, with an estimated net worth of £14 billion.