The steel magnate, who is worth £19.25 billion, has made an inquiry about the possibility of taking over the midlands club from David Sullivan and David and Ralph Gold.

Mittal, who is based in the UK, has not so far followed up his initial interest in Blues who have become a more attractive commodity following their return to the Premiership.

City are already the subject of interest from a mystery Far East businessman who is planning to make a formal bid later in the week if auditors are satisfied after going through the club's books.

But 56-year-old Mittal, who last year bought Arcelor, the world's second biggest steel-maker for £17.8 billion, is maintaining a watching brief.

Mittal has twice the personal fortune of Chelsea owner Roman Abramowich and Blues could be transformed into a major power if he took control.

Sullivan and the Golds, who would relinquish control for around £50 million, would be happier with a quick sale of City rather than a long drawn-out affair if their time at the club is to end after 14 years.

In the meantime Birmingham manager Steve Bruce is pressing ahead with his plans to try to strengthen his squad for next season.

But he suffered a setback with West Brom rejecting a joint £5 million bid for Diomansy Kamara and Jason Koumas.