Lady Anne Glenconner has defended Princess Diana's 'generous' stepmother after Earl Spencer's disparaging remarks about the late Countess Spencer in his new book Swan Song.

Princess Margaret's former lady-in-waiting, whose new book Trunks & Tiaras is being serialised by the Daily Mail, said Raine Spencer was 'wonderful' with John Spencer, the 8th Earl Spencer, after their marriage in 1976.

Lady Glenconner, 94, credited Raine, who died ten years ago at the age of 87, for 'saving' John's life, and also praised her as a fabulous godparent to her daughter May.

'I liked her,' she told Hello! magazine. 'I was godmother to her daughter, Charlotte, and she was godmother to my daughter, May, and she was very generous to her.

'I think, from the children's point of view, she probably was difficult, but she was wonderful with Johnnie [Earl Spencer] – she saved his life when he was ill. And then, interestingly, she became great friends with Diana.'

Charles Spencer portrayed the late British socialite unflatteringly in Swan Song – including detailing the infamous fight between Raine and Diana at Althorp House in 1989.

He recalled the moment Diana pushed her stepmother down the stairs after Raine said she felt 'sorry' for the then-Prince of Wales because he was married to 'someone quite as stupid' as her.

Robert Hardman, the Daily Mail's royal biographer, noted the 'charge sheet against Lord Spencer's late stepmother, Raine, runs on for pages' in Swan Song. 

Writing in the Daily Mail, he suggested Raine's marriage to Charles' father John, and the years they spent together at Althorp House, still 'clearly rankles' the aristocratic historian. 

In his divisive memoir, Charles claimed Diana found out about their father's marriage to Raine via the newspapers and criticised his stepmother for selling many of the Althorp estate's assets. 

He described it as Raine 'feathering her own nest for when [our] father was no longer around'. 

In his book, which was released ahead of the 30th anniversary of Diana's death, Charles said he and Diana spent their school holidays at Althorp House, but preferred the outdoors because Raine had a 'total aversion to the countryside and to exercise'. 

'We were guaranteed to be free of Raine outside,' Charles wrote about the 'stepmother we could not stand'. 

That there was no love lost between Charles and Raine is well known. 

The Telegraph reported that the Spencer siblings nicknamed John's second wife 'Acid Raine', while Diana's former butler, Paul Burrell, claimed they would all sing 'Raine, Raine, go away' when they saw her. 

But in one of the book's most damning passages, Charles detailed the moments leading up to Diana pushing Raine down stairs – which happened the day before he was to marry his first wife, Victoria Lockwood, in 1989.

Charles recalled family members, including his mother Frances Shand Kydd (who divorced Earl Spencer in 1969), arriving at Althorp House for tea. 

When a member of staff on Raine's instructions seated Frances separately from the rest of the wedding party, Diana became outraged and reportedly said: 'This is Charles’s mother, Raine, and she has to be included with the rest of us – not sent to a separate room like some naughty child! Do you really have no idea how to behave?' 

As tensions escalated, Raine lashed out at Diana, whose marriage to Charles was steadily deteriorating, and said: 'I have always felt so very sorry for the Prince of Wales, marrying somebody quite as stupid as you.' 

Diana paused then 'hooked a long leg round Raine's calves before shoving her down the carpeted staircase', the Earl wrote, adding the family never spoke of the incident again. 

Raine met Diana's father Johnnie, who was recently divorced from Frances Shand Kydd, at a cocktail party when she was still married to her first husband, Gerald Legge, the future 9th Earl of Dartmouth.

After divorcing her husband, Raine and Johnnie married in 1976 and she became as an unwelcome addition to the Spencer family, and was often ganged up on by the children.

Royal biographer Ingrid Seward said: 'All the Spencer children behaved very badly to Raine; it wasn't just Diana. They were purposely ganging up on her.'

After moving into Althorp, the Spencers' ancestral home, Raine began to redecorate, which included selling antique furniture that had been in the family home for hundreds of years and gilding picture frames in bright gold paint.

'I think when the children found out what Raine was doing at Althorpe, they loathed her even more and they did try and stop her,' Raine's biographer Angela Levine said.

'They talked to their father, but I think he was scared of not supporting Raine because he needed her so much at every level of his life', especially after his stroke in 1979.

Raine was invited to Diana and Prince Charles' wedding but was kept at the back of Westminster Abbey while her parents sat at the front, and when Johnnie died in 1992 she was kicked out of Althorp by Charles with her belongings in black bin liners.

However, Diana and Raine reconciled after Johnnie's death, with the princess expressing her gratitude for all the 'love' she had shown her father.  

After Charles and Diana divorced in 1996, Diana made the surprising move of inviting Raine to dinner at Kensington Palace.

'Diana was fully aware of what she was doing, she knew that this was a U-turn day. She knew the Spencer family would not be very happy but she couldn’t care less because she thought it was time Raine came back,' Paul Burrell said in the 2017 documentary Princess Diana's 'Wicked' Stepmother.

For the last year of Diana's life the pair remained very close and spoke on the telephone every morning.

Thirteen months after she was removed from the Spencer family home, she married her third husband, Count Jean-François Pineton de Chambrun, but the marriage lasted just three years.

Raine died in October 2016 following a short battle with cancer.