Mrs May was mocked for her enthusiastic curtsy on Wednesday afternoon, as she greeted the Duke of Cambridge at a Battle of Amiens centenary ceremony in France.
The Prime Minister’s 12 inch dip made headlines, with members of the public deeming her bow as “awkward”, believing Mrs May may have sunk to the floor a little too deep.
Royal etiquette experts say that a curtsey should in fact be “discreet, brief movement” and not a “ballet plie”.
Adam Patridge, etiquette expert said: “A curtsy should be a discreet, brief movement and not a ballet plie, or a grand, sweeping descent to the ground.
“From a standing position, transfer your weight to one foot (usually the left). Place the ball of your other foot behind and slightly to the outside of your standing ankle.”
Sarah Ferguson is also known to dip particularly low when performing the gesture.
On 23 June, the Duchess of York greeted the Queen with a curtsy as she arrived at the Parade Ring at Royal Ascot, bowing nearly 20 inches to the floor, with her knees almost touching the grass below her.
Royal etiquette expert Jean Broke Smith said: “If you’re meeting the Queen, she will always put her hand out to you and that is your cue to curtsy.
“You should not look at her as you curtsy but keep your eyes lowered.
“Only as you come back up should you meet her eyes and if she is offering you her hand you can shake it. Otherwise, keep you hands to yourself.”
The curtsy is performed when a girl or woman meet someone more senior in social ranking, and is derived from the word “courtesy”.
The action is a way to show respect to those of higher status, and is often performed when members of the public and royals meet the Queen.
It also performed when government officials meet members of the royal family.
However, Mr Patridge said that members of the public can choose whether they wish to curtsy or not, and are not obliged to perform the greeting to royals.
He said: “Members of the public are not bound to the traditions and protocols of the Royal Family, although they can choose to curtsy if they wish.
Ms Smith added: “I remember when my son was at Eton with the two princes and Diana would visit.
“For some of the parents, she was simply ‘another school mum’ but I noticed others gave a little curtsy or nod when she walked into the room — I thought that was a nice touch.
“Diana didn’t seem to mind either way.”
From the 17th century onwards, the curtsy became gender specific, with men adopting the bow while women performed the curtsey.
From the Victorian times, women started curtsying even lower because their dresses were so large a small curtsey would not be have been obvious.
When women started wearing Edwardian dresses, they would hold up their skirts to curtsey.
Ms Smith added: “There’s no rule as to how many inches from the ground you must go — it depends on how flexible you are and how good you are with your core strength and balance.
“The Duchess of York’s recent curtsey at Ascot was a little over the top, however.”