Sir Philip Hampton will take over from Sir Christopher Gent as chairman of GlaxoSmithKline on May 7, nearly four months earlier than expected.

The appointment of Sir Philip (pictured), outgoing chairman of the Royal Bank of Scotland, was announced last autumn and he was due to take over from September 1 this year. However, RBS has announced his successor, Sir Howard Davies, who will take over on August 31.

This means Sir Philip will be chairman of both GSK and RBS for three months. He joined the drug giant’s board as an independent non-executive director last month and will become deputy chairman on April 1. He will take over at the top when Sir Christopher steps down at GSK’s annual general meeting on May 7.