(Sharecast News) - Tesco has reportedly begun sounding out candidates to replace long-serving chairman John Allan.

According to Sky News, the supermarket chain is working with headhunters to identify a successor. City sources told Sky that a number of heavyweight boardroom figures had been approached in recent weeks about the role.

Allan will step down next year, by which time he will have served for nearly a decade and be 'timed out' under corporate governance guidelines which mean that he would no longer be regarded as independent.

The search for his successor is being led internally by Byron Grote, the former BP finance chief, who himself is due to step down from the Tesco board this year.

Lygon Group, a search firm, has done much of Tesco's boardroom recruitment work in recent years, although Tesco declined to confirm that it was overseeing the chairman process.

Allan, a former president of the CBI, has been an outspoken figure during his tenure as Tesco chairman, and has been lavishing praise on the Labour Party leadership in recent months, Sky said.

A former chairman of Dixons Stores Group - now known as Currys - he has also sat on the boards of blue-chip British companies including 3i Group, Royal Mail and Worldpay.