Sir John Major claims Margaret Thatcher's dementia was behind her criticism of his leadership

Sir John Major has claimed Margaret Thatcher’s dementia was behind her criticism of his leadership after he took over as Prime Minister.

Sir John, who replaced Baroness Thatcher in 1990 after she resigned following a leadership challenge from Michael Heseltine, said subsequent “sniping” from his predecessor “didn’t sound to me like the Margaret I had come to know".

The former Conservative PM said he understood “as a matter of common humanity” why his rival may have harboured ill feeling towards him.

But he said his belief that she was ill meant he could bear the criticism “though it was uncomfortable”.

Speaking at The Politics Festival at Kings Place in central London, he said: “Margaret was ill. I think for most of the time I don’t think anyone quite knew when her illness started.

“But the comments that came out from Margaret after she left office didn’t sound to me like the Margaret I had come to know.  

“You have to realise there are several Margaret Thatchers. There is the real Margaret Thatcher… that most of us who worked with her knew and there is the Margaret Thatcher of legend who is an artificial construct and very different.

“So although it was a very difficult period when she was sniping, when she was bored, not very well and out of government, I don’t really think that was the Margaret Thatcher that I knew and so I could bear that though it was uncomfortable.”

Sir John said he regularly met with Baroness Thatcher after she had left Number 10 and the pair often dined together at Downing Street.

He described their relationship after he was elevated to the top job as “entirely clement”.

Asked if he thought Baroness Thatcher’s illness had started to influence her outlook in those early days after he became Prime Minister, Sir John said: “Well, I do actually. She was very frustrated once she left Downing Street because she had been there a very long time.

“She saw it as her job and I think it was quite hard to leave the way she left when she had fought three general elections and won three general elections to be removed in the way that she was removed I think was extremely difficult.

“Then to see someone else who she had nurtured from the backbenches in her position purely as a matter of common humanity you can understand how difficult that would have been for her and I think I did understand that even at the most difficult moments.”

Baroness Thatcher died of a stroke in April 2013 at the age of 87 following a long battle with dementia.

Documents released by the National Archives in 2017 revealed in plain terms how quickly the views of  Baroness Thatcher and Sir John diverged after he replaced her and the forthright advice she felt able to offer.

She had warned her successor that he was in danger of making an “historic error” with his handling of the economy, only weeks after she had backed him to take power.

The former Prime Minister rounded on her former protege and said he risked repeating Winston Churchill’s mistake of keeping the level of the pound too high and would drive the country into recession.

Sir John also yesterday suggested that “people who advertise themselves as great supporters of Margaret” were actually undoing one of her “greatest achievements” by “trying to take us out of the single market”.

Outlining his opposition to Brexit, he said the UK was making a “monumental error” by leaving the European Union.