The fashion world was brought to a standstill on Thursday as a colossus announced the end of an era.

The Vogue headquarters in New York was shocked when Anna Wintour, aged 75, unexpectedly announced her resignation as editor-in-chief.

In her 37-year reign, Wintour reinvented the magazine, turning it into the influential force it is today.

Known as much for her trademark sunglasses and sleek bob haircut as for managing the title with an iron fist, she rose to become the most dominant woman in publishing.

Her decisions had the power to set international style trends and, in doing so, make or break designers.

Even though she will maintain her positions as global chief content officer at Condé Nast, Vogue’s parent company, and global editorial director at the magazine, the revelation still left staff in a state of disbelief.

The Daily Mail understands that the British fashion icon announced the news at the end of a regular meeting with senior colleagues – and simply said that she was seeking a new Head of Editorial Content (HOEC) in the US.

‘I find that my greatest pleasure is helping the next generation of impassioned editors storm the field with their own ideas, supported by a new, exciting view of what a major media company can be,’ Wintour said.

‘And that is exactly the kind of person we need to now look for to be HOEC for US Vogue.’

A source who was at the meeting told the Daily Mail that it had come as ‘a shock’ when Wintour – seemingly out of the blue – revealed the change.

A source who was at the meeting told the Daily Mail that it had come as ‘a shock’ when Wintour – seemingly out of the blue – revealed the change 

In her 37-year reign, Wintour reinvented the magazine, turning it into the influential force it is today (Pictured: Wintour’s first cover in 1988)

It was ‘like finding out that God is stepping down from being God,’ the source said of Wintour’s announcement, which comes after the fashion maven’s tenure at the media company (Wintour pictured in 2002)

It was ‘like finding out that God is stepping down from being God,’ the source said.

‘She wasn’t warm and fuzzy, and she was a real taskmaster – but she was our taskmaster.

‘We all figured out what she wanted and how to please her. There is a level of familiarity there. We know what she wants and how to give it to her. Now it’s an unknown.

‘It wasn’t an emotional announcement. A couple of them [staff members] got misty but it wasn’t like there was weeping and gnashing of teeth.

‘We’re all just trying to figure out what the new normal will look like.’

As chief content officer, Wintour oversees every brand within the Condé Nast stable worldwide, including Wired, Vanity Fair, GQ, AD, Condé Nast Traveler, Glamour, Bon Appetit, Tatler, World of Interiors and Allure among others.

The new head of editorial content for US Vogue will report to her.

Wintour became editor-in-chief of Vogue in 1988 and is credited with transforming the fashion magazine.

The Devil Wears Prada, a novel by her former assistant Lauren Weisberger, helped shape her reputation for a frosty, extraordinarily demanding and often harsh leadership style.

In the film adaptation, Anne Hathaway takes the role of university graduate Andrea Sachs, an assistant to the tyrannical magazine editor Miranda Priestly, played by Meryl Streep.

Priestly is portrayed as cruel, vindictive and a boss to whom her employees could never say ‘no.’

The source, however, told the Daily Mail that comparisons between Priestley and Wintour are not entirely fair.

‘Everyone thinks she’s Miranda Priestley, and in many ways she is.

‘But she’s more human than that. She’s not my friend but I can respect the amazing product we’ve produced for so long.’

‘Everyone thinks she’s Miranda Priestley, and in many ways she is,’ the source said

They added: ‘But she’s more human than that. She’s not my friend but I can respect the amazing product we’ve produced for so long’ (Pictured: Meryl Streep as Miranda Priestley in The Devil Wears Prada)

Even though Wintour will maintain editorial control of Vogue, there is still uncertainty about the future among staff.

The hunt is on for someone to fill her Manolo Blahnik slingbacks at the forefront of a fashion behemoth with 28 international editions at a time when the publishing industry is under threat.

Speculation about who will take over day-to-day running of the magazine has already begun.

‘Everyone’s nervous about what the shakeup will be,’ our source added.

Wintour’s first job was on the now-defunct Harpers & Queen. Before she took over at Vogue as editor-in-chief, she was its creative director.

She then went back home to British Vogue, where she served as editor-in-chief from 1985 to 1987, before rejoining American Vogue.

Her famed covers included appearances from A-listers such as Oprah Winfrey, Madonna, Ivana Trump, Kate Moss, Naomi Campbell, Christy Turlington and Cindy Crawford.