Fit for a Princess: The Hardy Amies exhibition

He dismissed Noël Coward as "common", told Marlene Dietrich never to wear trousers, and was desperate to dress Wallis Simpson. As dressmaker to the Queen for almost 40 years and a leading Savile Row tailor, Hardy Amies's career offered him an unrivalled insight into the world of the rich and famous.

Now the public will also be able to peer into his world, as his vast archive, containing unseen photographs of the royal family, letters from Cecil Beaton and Margaret Thatcher, and intimate diaries, sketches and clothes are unveiled.

The exhibition, which goes on show at the label's fashion house – 14 Savile Row – will include more than 7,000 of the couturier's sketches, from unseen drawings of a young Princess Elizabeth in the year she became Queen, to sketches of his costumes for the film 2001: A Space Odyssey.

"Hardy Amies was one of the most important British couturiers of the 20th century," said Rosemary Harden, manager of Bath Fashion Museum. "Historically, British fashion had not been as established as French fashion, but Amies was key in changing that. We have a suit of his from 1948, which shows how he took the French 'New Look'– with nipped-in waists and full skirts – and made it very British."

The designer, who was knighted in 1993 and died in 2003, opened his first couture house at 14 Savile Row in 1946, after a stint in the British intelligence service during the Second World War. Just one year later, his designs appeared on the cover of Vogue, and in 1955 he was appointed official dressmaker to the Queen.

The son of a civil servant, Amies was famously impressed by wealth and the aristocracy, and the exhibition highlights the designer's snobbish tendencies and often acerbic personality. "He could be very funny and quite vicious sometimes in his asides," said Freddie Fox, who worked alongside Amies as the Queen's milliner. "That was fine if you were on the right side; if you were on the other side it wasn't funny at all."

Notes by Amies also reveal that his very public dislike of Wallis Simpson – the American divorcee who scandalised the royal family when she married the former Edward VIII – was exaggerated, admitting he liked "her understated appearance and clean lines".

"He would have liked to have dressed her, but couldn't because there would have been a conflict of interest," said Austin Mutti-Mewse, the exhibition's curator. "The Queen had softened towards Wallis by this point, but there was still a rift."

The designer admitted that he thought that men were better than women at designing clothes for women. In a letter to a friend, he wrote: "Coco Chanel is an extraordinary woman and a great designer, but even she doesn't have the objective view."

Also on display will be letters from Amies's friends and clients, such as Nancy Reagan. Some of the designer's famous friends – including Princess Michael of Kent, Jeremy Irons and Lady Astor – have taken part in a documentary about his life which will be screened inside the exhibition.

Timed to coincide with the 100th anniversary of his birth, the exhibition, Sir Hardy Amies: A Century of Couture, will open on 2 November. It is the first time a British couture house has opened its archive to the public.