The family of Baroness Kinnock has announced the death of the “proud democratic socialist”, a former politician and wife of ex-leader of the Labour Party Lord Kinnock.

In a statement to PA news agency, her family said: “It is with the deepest sorrow that we announce the death of Glenys Kinnock.

“Glenys died peacefully in her sleep in the early hours of Sunday morning, at home in London.

“She was the beloved wife and life partner of Neil, the cherished mother of Steve and Rachel and an adored grandmother.

“Neil was with her in her final moments. They had been married for 56 years.

“A proud democratic socialist, she campaigned, in Britain and internationally, for justice and against poverty all her life.”

Baroness Kinnock’s family said they were “devastated” by her death.

Continuing their tributes to Lady Kinnock, her family said: “Passionate to the end about education, she was a valued and respected school teacher before she began her own political career, as a Member of the European Parliament, then being made a peer in the House of Lords from where she served as minister for three of the great passions of her life, Europe, Africa and the UN.

“She was a great friend to many people and causes and was truly loved.

“Glenys endured Alzheimer’s after being diagnosed in 2017 and, as long as she could, sustained her merriment and endless capacity for love, never complaining and with the innate courage with which she had confronted every challenge throughout her life.

“The family is of course devastated and and would ask that their privacy be respected. Funeral details will be communicated in due course.”

Sir Keir Starmer paid tribute to Baroness Kinnock, who he called a “true fighter for the Labour Party”, after her death was announced on Sunday.

The Labour Party leader said: “On behalf of the whole Labour Party, I want to pay tribute to Glenys Kinnock on the sad news of her passing.

“Glenys was a passionate lifelong campaigner for social justice at home and abroad.

“She supported Neil through his leadership and went on to have an impressive political career of her own as a member of the European Parliament, in the House of Lords and as a minister in the last Labour government, focused on Europe and Africa.

“Neil and Glenys had the most wonderful partnership, there for each other through thick and thin, with a love and commitment that was instantly obvious when you saw them together. As the family have detailed, in recent years that meant looking after Glenys as Alzheimer’s did its worst.

“But what we will all remember is Glenys as a true fighter for the Labour Party and the values of the labour movement, a pioneering woman, to whom we owe an enormous debt. My sincere condolences to Neil, Stephen, Rachel and all the family at this sad time.”