In a statement, the 130-year-old bourse says its board will now "begin a formal process which may or may not lead to an acceptable offer for the company being received".

The exchange's members, who own it, think it could be worth more than £1 billion, according to the Financial Times.

Although the LME has refused to name its suitors, CME Group, ICE and Singapore's SGX, which all offer metals trading on a smaller scale than the target, are being widely reported as the most likely bidders.