The secret posh pecking order: Our high society snitch reveals the REAL ranking of blue bloods, from the top-tier toff every husband wants to bed, to the C-list woman William calls when he wants to blow off steam

Pictured on the pages of society magazines at parties and weddings, they are a tribe known for their peaches-and-cream complexions, sparkling jewels and oh-so tasteful attire. Yet being a member of the aristocratic set in the 21st Century isn’t all champagne and castles. As a long-time observer of the in-crowd, I can tell you that behind the perfect teeth, and even more perfect manners, these elite circles harbour intense rivalries.

The ultimate test of who is ‘in’ is still judged by proximity to the Royal Family. Beyond that, social influence and good old-fashioned money are the things that count. My list is also informed by who gets invited to the best shooting weekends – valuable social currency in this world – and who couldn’t even get a table at Pizza Express in Woking. So from the chatelaine of one of the country’s finest stately homes to the singer who once snared one of Britain’s most eligible bachelors only to now find herself sliding in the wrong direction, here’s my definitive insider’s guide to who’s up and who’s down...

Top of everyone’s dream guest-list is Rose Hanbury, the Marchioness of Cholmondeley (pronounced ‘Chumley’). The 40-year-old entered the A list in 2009 when she married the 7th Marquess of Cholmondeley and became chatelaine of Houghton Hall, a 106-room neo-Palladian pile in Norfolk built for Britain’s first Prime Minister Horace Walpole, bedecked with chinoiserie and hand-printed wallpaper. Top of everyone’s dream guest-list is Rose Hanbury, the Marchioness of Cholmondeley.

She splits her time between that mansion and London with her dashing film director husband, aka David Rocksavage, who is 24 years her senior and worth a cool £60 million. Rose has remained top-tier ever since her marriage – and is a source of endless fascination in high society, which is why she gets invited to everything. However, very few ‘stiffy’ invitations – the nickname for those written on card so stiff it can’t be folded – are grand enough for her to accept, so it’s tricky to earn a place on her marble mantlepiece.

Part of her allure is that she’s enigmatic and choosy about her friends. Invitations to Houghton are like gold dust. She tends to mix only with a trusted inner circle of fellow Norfolk ‘Turnip Toffs’, the name given to the county’s landowning set. At parties, I have noticed that Rose often slinks into the shadows, preferring private chats with girlfriends to dancing on tables. More beguiling in real-life than she is in photographs (she’s not so consistently photogenic as her neighbour the Princess of Wales), most husbands secretly – and not so secretly – fancy Rose.

Interestingly, Rose is not the only one in the family to go for an older man. Her lesser-known sister Marina, 42, is married to Ned Lambton, the 7th Earl of Durham, who is 21 years her senior. When it comes to royal circles, Rose ticks this box too. Much mischief is spoken of her being the Princess of Wales’s ‘rural rival’ in Norfolk’s social hierarchy but they are close friends. One wouldn’t imagine that the Princess’s sister Pippa would have named her younger daughter ‘Rose’ if there was any tension between the two women.

Talking of Pippa Middleton, she is on the A-list because everyone desperately wants an invitation to her new super stylish stately home, but it may as well be Fort Knox. Pippa Middleton is on the A-list because everyone desperately wants an invitation to her new super stylish stately home, but it may as well be Fort Knox. To say the Georgian property in Berkshire is an interior designer’s dream would be giving too much away about its previous occupant, who I can’t name because Pippa doesn’t want people to guess where she lives. I can tell you this though: her kitchen garden (a high-society must have) is to die for.

With a future Queen for a sister Pippa, 41, could have trashily traded on her royal links for fame and money, but instead, after marrying hedge fund manager James Matthews, she gave up her vast Chelsea townhouse and retreated to the country to become an Earth mother, opening a petting zoo and nursery school. The hallmark of a true A-lister is an abhorrence of drama, flashiness and fame. Take the Duke of all Dukes – handsome Hugh Grosvenor, 34, the 7th Duke of Westminster.

The advance hysteria got a little out of control before he married Olivia Henson, 32, last year. I travelled to Chester Cathedral expecting a full royal wedding-style event, but in the end the groom insisted on everything remaining as low-key as possible. Handsome Hugh Grosvenor, the 7th Duke of Westminster, at his wedding to Olivia Henson in June last year. But then again, his bride Olivia, a former account manager for an ethical food firm who was introduced to the Duke by friends, is a mere civilian like the rest of us. Or at least she was until she married the richest man under 40 in the UK with almost £10 billion at his disposal.