A bookish blonde, Lady Gabriella Windsor is known as one of the quieter members of the Royal Family.

But the daughter of the Queen’s first cousin, Prince Michael of Kent, has found herself the subject of an extraordinary article penned by her ex-boyfriend in which he claims they took MDMA – ecstasy – at Windsor Castle and swam naked in the Queen’s swimming pool at Buckingham Palace.

What’s more the writer, Aatish Taseer, who dated the bluestocking for three years until 2006, touches upon the issue of racism and the Royal Family.

He alleges that ‘royals and Nazis go together like blini and caviar’ and claims that Lady Gabriella’s mother, Princess Michael, once owned two black sheep at her former Gloucestershire home, which she named Venus and Serena after the African-American tennis sisters.

Royal insider: British journalist Aatish Taseer, 38, dated Lady Gabriella Windsor, affectionately known as 'Ella', for three years after meeting through friends in New York in 2003

Lavish lifestyle: Taseer, a journalist, accompanied the royal, now 37, to society events

Seal of approval: Taseer with Lady Gabriella and her mother, Princess Michael of Kent in 2004

Last night there was stony silence from Buckingham Palace and a spokesman for the Michaels, who live at Kensington Palace, who said: ‘There won’t be any comment on the story.’

A friend of Ella, as she is known to her friends, was reported as describing the allegation as ‘fiction’.

‘Aatish is a novelist. He has an active imagination,’ they said.

But the allegations have left senior courtiers reeling, particularly the suggestion that Lady Gabriella, who while only 50th in line to the throne is still a regular at royal events and is likely to attend next month’s royal wedding, allegedly took an illegal drug at one of the Queen’s official residences.

Journalist Taseer – who once dressed up as a sexual health campaigner called Captain Condom – became so close to fellow writer Lady Gabriella, now 37, during their relationship that they were tipped to marry.

Going for a swim: The writer said he and Gabriella 'swam naked in the Queen's pool in Buckingham Palace' (pictured in a file photo)

Parents: Lady Gabriella is the daughter of Prince and Princess Michael of Kent (pictured in a file photo)

Home: Taseer described how they 'hung about' Kensington Palace (pictured), where Lady Gabriella's parents, Prince and Princess Michael of Kent, live

Who is Lady Gabriella Windsor? Lady Gabriella Windsor, 37, is the daughter of Princess Michael of Kent and Prince Michael of Kent - a first cousin of the Queen. Lady Gabriella, known as 'Ella', is currently 50th in line to the British throne. Educated at Downe House School in Cold Ash, Berkshire, Lady Gabriella obtained an MPhil degree in Social Anthropology from Linacre College, Oxford. She also studied at Brown University in the US. During their three-year relationship, Lady Gabriella and journalist Aatish Taseer were often seen at society's biggest parties. The pair parted ways in 2006. She is now keeps a low profile. Lady Gabriella is believed to work as an arts consultant and writer for Branding Latin America, based in London. The royal shares her birthday with the newborn Prince Louis of Cambridge. Advertisement

London-born Taseer, whom Princess Michael once described as ‘one of the most handsome men I have ever met’, is the son of a wealthy Sikh mother and a Muslim newspaper proprietor from Pakistan. His father, a politician, was assassinated in 2011.

Writing in Vanity Fair magazine, Taseer describes how, in a ‘louche past life’, he was ‘almost’ a member of the Royal Family.

He says: ‘For three surreal years, Ella and I hung about Kensington Palace; we swam naked in the Queen’s pool at Buckingham Palace; we did MDMA in Windsor Castle; and we had scrapes with the British press.’

No further details of the alleged incidents were given.

Taseer recalls how he was ‘waved in’ to Kensington Palace (then a home for minor royals, which he described as being a cross between a military hospital and an old people’s home) by policemen who said: ‘Ah, you’re the Indian fella who’s going with Gabriella.’

In the US magazine, which is also on sale in the UK, he writes at length about Princess Michael – dubbed Princess Pushy for her imperious ways.

Of her denilas of racism, he says: ‘I would have liked to believe her, but I had my doubts...royals and Nazis go together like blini and caviar...everyone above a certain age in Britain is at least a tiny bit racist.’

Making a statement: Prince and Princess Michael of Kent at the wedding of Crown Prince Leka II of Albania in 2016. Taseer said Princess Michael did not possess the understated nature of other royals

High profile romance: Many believed Taseer and Lady Gabriella (pictured in 2006) would wed

He adds: ‘Princess Michael, though generally free of British colonial prejudices, and beyond reproach when it came to me, nevertheless invited trouble out of what felt like a desire to shock.

Black sheep named Venus and Serena The revelation that Princess Michael is said to have kept black sheep named Venus and Serena will cause further embarrassment to the Royal Family. Serena Williams is a good friend of Meghan Markle and is likely to be at her wedding to Prince Harry, which the princess is also sure to attend. The princess, the daughter of an SS officer, has been accused of racism several times over the years, most recently when she wore a Blackamoor brooch to meet Miss Markle, who is mixed race. In 2004 she was accused of telling a group of black diners in New York to ‘go back to colonies’, a claim she disputes. Taseer writes of the incident, which occurred while he was dating Lady Gabriella that she ‘feigned an odd mixture of injustice and contrition’: ‘I daren’t even say I want my coffee black any more. I say, “Without milk”.’ Advertisement

‘Most everybody thought she was “perfectly ghastly,” but I saw a nice side of Princess Michael. She could be funny, intelligent, generous, and she was a lot more industrious than the other royals-she wrote books and decorated houses! Her tragedy was she never understood that element of understatement that is so much the secret of survival for the Royal Family.'

He reveals: ‘She was of the firm belief that it was a bad idea for royalty to marry commoners.

‘“It’s all very well Ella marrying Mr Taseer from India or Pakistan,” she once said to me. “No one knows what to do with that. But the moment the girl down the road thinks she can be Princess, or Queen, it’s all over. The mystery is gone”.’

Taseer says his romance with Lady Gabriella wasn’t all ‘schlosses, boats and stag hunts’.

His abiding memory of rubbing shoulders with the Michaels was of ‘constant cutbacks and reduced circumstances’.

‘To fly with the royalty was to fly with Easyjet,’ he said.

He recalls one excruciating flight back from Sardinia, when the Kents were seated in the second row of their economy plane.

Family home: The Duke and Duchess of Cambridge now live at Kensington Palace with children Prince George, four, Princess Charlotte, two, and newborn Prince Louis

Laying low: Prince Harry and Meghan Markle live in a two-bedroom cottage on the grounds

‘A moment of silence ensued, then there was a dull roar on the jetway, and a planeload of lobster-red British tourists poured on to the flight, muttering, “Wot’s this, wot’s this?,” as they rushed past the grandson of George V, Emperor of India,’ he writes.

The Michaels live in a five-bedroomed apart in Kensington Palace, which makes them neighbours of the Duke and Duchess of Cambridge and Prince Harry and Meghan Markle.

For decades they used to pay a peppercorn rent for the property, courtesy of the Queen, but after a public outcry in the 1990s were forced to start paying a full commercial rate, estimated to be around £10,000 a month.

Neither receive any taxpayer funding, although they carry out a small number of duties on behalf of the monarch each year, and have to work as writers, speakers and, in the case of Princess Michael, as an interior decorator. It has led them to be dubbed the ‘rent a Kents’.

How Princess Pushy ‘told black diners to go back to the colonies’ and was ‘shocked’ to discover her father was a Nazi SS officer

Princess Michael once allegedly told black diners to 'go back to the colonies' and claimed not to know her father was an SS officer.

In 2004 she was branded a racist by a group in a New York restaurant after a row erupted over the noise she claimed they were making.

The royal was accused of slamming her hand down on the group's table, telling them: You need to quiet down.'

Restaurant boss Silvano Marchetto offered to move Princess Michael and her party to another room.

Before switching tables the royal is alleged to have said 'you need to go back to the colonies'.

The princess was reportedly challenged at the time and was said to have replied: 'I did not say "back to the colonies", I said you "should remember the colonies".

'Back in the days of the colonies there were rules that were very good.'

She is alleged to have continued: 'You think about it. Just think about it.'

One of the group, Wall Street banker Merv Matheson, who said: 'She has a problem and that problem is racism. She needs help.'

AJ Callaway was also caught up in the alleged row and was surprised to find out she was a member of the Royal family.

'I thought she was just a crazy woman. I still think she's a crazy woman,' he said at the time.

A spokesman denied that the princess made the slur, which reportedly arose from a confrontation about the group making too much noise in the Da Silvano restaurant.

In 2014 it was revealed her father, Baron Gunther von Reibnitz, was a high-ranking SS officer, which the Princess Michael claimed was shocking news to her.

He joined the Nazi party in 1930 but would escape to Bavaria in 1945 when it was occupied by the Americas.

Princess Michael was born Marie-Christine von Reibnitz during the final months of World War Two.

Historian Philip Hall unearthed the baron's Nazi link at the Berlin Document Centre, where evidence showed he had joined the SS three years before Hitler became chancellor.

He also found references to Baron Gunther von Reibnitz being recommended for an appointment by Herman Goering and he is believed to have fought on the Polish front.

After the war's end, the baron split from his family. The children and their mother headed to Sydney, Australia, and he settled in Mozambique, where he ran a citrus farm.

The Czech princess joined the British Royal Family when she married Prince Michael of Kent in Vienna in 1978 and would later claim her union with the Silesian was an arranged marriage.

She famously accused the British of racism in the 1980s when she said in an interview: 'The English distrust foreigners.

'I will never become British even if I live here the rest of my life.'

She was branded Princess Pushy until 2013, when she was described as Princess Cushy for whinging about the rent she paid to Kensington Palace.

Before 2010 she was paying just £69 a week in peppercorn rent, but would go on to pay £120,000 a year to stay at the palace, which has ten main rooms.

The new rent rate was imposed when the Queen was forced to restructure her grace-and-favour residences a few years ago to bring rents into line with present-day market values.

She also courted controversy when she told Tatler magazine she knew 'the real story' about Princess Diana following her death in 1997.