Dido Harding has announced she is stepping down as TalkTalk chief executive after seven years in the role.
Harding has also been a vocal opponent of BT's continued ownership of the Openreach broadband network, often calling for the two businesses to be split apart.
Shares in the group went up 8.5 per cent in early trading.
Harding will leave the top job in May, and will be replaced by Tristia Harrison, currently managing director of TalkTalk's consumer division, while Charles Bligh, currently managing director of TalkTalk business, will become chief operating officer.
Meanwhile, Charles Dunstone, who is non-executive chairman at the moment, will become executive chairman in May, after he steps down as chair of Dixons Carphone.
And analysts were clear Dunstone, who is the group's largest shareholder with a 31 per cent slice of shares, would be the person taking over. George Salmon, an analyst at Hargeaves Lansdown, said:
With Dido Harding announcing her departure this morning, Sir Charles Dunstone, co-founder of Carphone Warehouse, will be the man to lead the group forwards.
His main challenges will be rebuilding trust in the brand and improving relationships with customers. After all, the dark days of the cyber attack are still pretty fresh in people’s minds.
Meanwhile, Harding said: "After seven extraordinary and fulfilling years, during which we have transformed TalkTalk's customer experience and laid the foundations for long term growth, I've decided it's time for me to start handing over the reins at TalkTalk and focus more on my activities in public service."
"I am very proud to be handing over to the next generation of TalkTalk leadership who, together with Charles, have played such an integral part in the success of the business to date.
"Between now and May, we will work together on a handover that maintains focus on this years' performance and enables the new team to prepare for the next financial year and beyond."
Dunstone said: "Dido has been a tireless, energetic and effective force for good from the day she joined TalkTalk. As a result of her leadership and total commitment to all of us who work here and our customers, she has helped transform TalkTalk into a much stronger business. She leaves with our thanks and very best wishes for the future."