Currently chair of Alcoa, Steve Williams will join the engineering company’s board in September as a NED and chair designate.

A veteran of consumer sector boards, Alexander will become non-executive chair of the direct-to-consumer chocolate brand this week.

Fiona Clutterbuck will join the board as non-executive chair of the company in May, replacing Baroness Helena Morrissey.

Clive Bannister has been appointed chair designate and a non-executive director of the board of the insurance group.

Sir John Kingman will join as a NED and take over from Crawford Gillies as chair of the group’s ring-fenced banking arm, Barclays UK.

Sir Ian Cheshire will step down from the board of BT Group in order to take over as Landsec’s chair from Cressida Hogg CBE.

Julie O’Neill returns to the board as a NED and will succeed Robert Elliott upon his retirement from the role of chair in March.

Silver will join the board as a NED in June, and should succeed John Allan as non-executive chair in September this year.

Domenic De Lorenzo is to succeed Bill Ronald next year as chair of the global supplier of carbonated drinks.

From the new year, Brewis will become non-executive chair of the Nottingham-based fantasy war games producer.