Emma Walmsley to become FTSE 100's top female CEO

Ms Walmsley has been promoted from heading Glaxo’s consumer healthcare arm to chief executive designate and will replace Sir Andrew Witty when he retires next March.

She will join a small band of women at the top of some of the UK’s biggest listed companies, becoming the seventh female FTSE 100 chief executive.

There are also women at the helm of easyJet, Imperial Brands, Whitbread, Royal Mail, Kingfisher and Severn Trent.

But with Glaxo’s £80 billion stock market value dwarfing those other firms, she is likely to be the most powerful woman in the top tier.

Glaxo chairman Sir Philip Hampton, who is also leading a Government-commissioned review into boosting the number of women in executive posts at top UK companies, said her appointment follows a “very thorough and rigorous” selection process.

He added: “Emma is an outstanding leader with highly valuable experience of building and running major global businesses and a strong track record of delivering growth and driving performance in healthcare.”

But shares dipped nearly 1% after the announcement.

Market analyst Jasper Lawler said: “Some more vocal shareholders had wanted an outsider to help push through a change in GSK’s structure, and are selling shares in a show of disappointment.”

Ms Walmsley has headed Glaxo’s £6bn consumer healthcare arm since it was created in March last year as part of a joint venture with Novartis and has been a member of Glaxo’s corporate executive team since 2011.

She joined in 2010 from L’Oreal, where she worked for 17 years in a number of marketing and management roles.

“GSK is a company that leads both in science and in the way it does business. We have momentum in the group and as the demand for medical innovation and trusted healthcare products continues to rise, we have the opportunity and the potential to create meaningful benefits for patients, consumers and our shareholders.”