Ken Livingstone, the former Labour MP and mayor of London, has been diagnosed with Alzheimer’s disease, his family has announced.

The 78-year-old is being “well cared for by his family and friends” as he lives a “private life” in retirement, they said in a statement to the PA news agency.

It said: “In response to media enquiries, the Livingstone family today announce that Ken Livingstone, ex-MP for Brent and former mayor of London, has been diagnosed with and is living with Alzheimer’s disease.

“Although a previously prominent public figure, Ken is now retired and lives a private life. He will no longer be available for any media interviews or requests and we will not be responding to any media questions or enquiries.

“Ken is being well cared for by his family and friends and we ask you for your understanding and to respect his privacy and that of his family.”

There are 944,000 people estimated to be living with dementia in the UK, according to Alzheimer’s Research UK, and the diagnosis rate in England was 62% in 2022.

The chief executive of the Alzheimer’s Society, Kate Lee, said: “We are really sorry to hear that Ken Livingstone is living with Alzheimer’s disease. Our thoughts are with him and his family.

“We can see from the high-profile individuals who have recently spoken about their dementia diagnosis, including Alastair Stewart and Fiona Phillips amongst others, how prevalent dementia is.

“One in three people born in the UK today will go on to develop this devastating condition. We’re grateful to Ken’s family for being open about his diagnosis, which will really help increase public understanding.”

Having largely retreated from public life in recent years, Livingstone was a prominent figure in politics for more than four decades.

In 1971 he was elected to Lambeth borough council. He was leader of the GLC from 1981 until 1986, and a year later he was elected the MP for Brent East in north-west London, where he served between 1987 and 2001.

The former lab technician also served two terms as mayor of London from 2000-2008.

A Labour member for more than 50 years, Livingstone was expelled from the party in 2000 after challenging Frank Dobson, the party’s official candidate in the London mayoral election race. He was later readmitted to the party by Tony Blair.

During his time at City Hall he was involved with London’s successful bid for the 2012 Olympic Games and in dealing with the aftermath of the 7/7 terrorist attack in 2005.

Livingstone was handed a four-week suspension from office in 2006 for comparing a Jewish journalist to a concentration camp guard. The suspension was overturned in court.

Livingstone lost City Hall in 2008 when he was defeated by Boris Johnson and a failed bid to return to office in 2012 marked the end of his electoral ambitions.

In 2016 he was suspended from the Labour party over comments he made in a radio interview that Adolf Hitler “was supporting Zionism before he went mad and ended up killing 6 million Jews”.

Livingstone apologised for his remarks at the time but denied that he was guilty of antisemitism.

In 2018, Livingstone announced he was resigning from the Labour party, saying the issues around his suspension for alleged antisemitism had become a distraction.