Sharon White has formally taken the reins of troubled retail group the John Lewis Partnership.

White gave her maiden speech as chair at a meeting of the employee-owned group’s council, held at one of its staff retreats, the Odney Club in Berkshire. Her predecessor Sir Charlie Mayfield also spoke at the event which was attended by around 200 staff, with many more watching online.

The changing of the guard comes at a difficult time for the group which owns the eponymous department stores as well as Waitrose. Profits at the department store chain have collapsed and staff – called “partners” within its democratic structure – have been warned they could miss out on their annual bonus this year. The group, which has stopped publishing weekly sales figures, did not release the text of either speech.

One of Mayfield’s last acts as chairman was to announce a new company structure that has involved merging John Lewis and Waitrose, enabling them to be run more cost-effectively by one eight-strong executive team rather than two separate boards.

The latest recruit to this new line-up is Nina Bhatia, who has been handed responsibility for strategy and commercial development across both brands. Bhatia had “tremendous commercial and strategic experience”, White said. Rob Collins and Paula Nickolds, the managing directors of Waitrose and John Lewis respectively, have left the business as part of the shakeup.

Bhatia is joining from Hive, the connected heating, lighting and home security business owned by Centrica, where she was managing director. Prior to that the former McKinsey management consultant led one of British Gas’s home services businesses.

She said that the John Lewis “purpose and its two incredibly strong brands resonate strongly with me. I look forward to developing a strategy for the partnership that is relevant to our customers, is built on trust and delivers commercial value.”