Pessina, who remains the largest shareholder in Walgreens Boots Alliance with a 17% stake, will replace Jim Skinner as executive chair of the pharmaceuticals giant as soon as a new chief executive is found. 

Pessina orchestrated the combination of Walgreens and Alliance Boots back in 2015 and the group continues to own the Boots chain in the UK.

Although Boots has suffered a turbulent period of high street trading – it warned earlier this month that it would axe 4,000 jobs following the coronavirus pandemic – it continues to operate almost 2,500 stores and employs 54,000 staff.