A collection of never-before-seen photographs of the Royal Family, including candid snaps of a young Prince Charles, are set to be auctioned off next month at Gorringe’s Auctioneers in Lewes, East Sussex.

The photos show the young Prince larking about at Windsor castle, including snaps of him peering over the parapet at Windsor Castle and him dressing up in a man's overcoat.

Former Grenadier Guard-turned-schoolmaster Michael Farebrother took the photos of the young Prince Charles back in the mid-1950s when he served as a private tutor to the King in waiting.

Mr Farebrother, who died in 1987 at the age of 67, had been posted to Windsor Castle during the Second World War and corresponded with the royals for the next 40 years, including several lengthy handwritten letters from the Queen.

The collection of Mr Farebrother's photographs, memos, and letters that were kept in a cloth-bound album and is expected to fetch up to £80,000 (around $146,000) at the auction on December 7.

Among the collection is a letter from the Queen who candidly discussed her feelings on The Troubles after learning of the news of the death of Lord Louis Mountbatten, who was killed by an IRA bomb at Mullaghmore, County Sligo, Ireland, in August 1979.

The Queen wrote in the letter: 'One can only pray that he will not have died in vain and that some good may come of this terrible act of blowing up a family on holiday and will shock people into doing something about Ireland - if only their opinions were not so entrenched.'

It can be noted that it is a royal protocol to not discuss politics. However, Her Majesty, who rarely breaks royal protocols, expressed her doubts that the troubles in Northern Ireland would ever be resolved in her note to Mr Farebrother.

Her Majesty has also written to Mr Farebrother to disclose her sentiments over the death of her father in February, expressing her 'emptiness and loneliness' and 'unbearable' sorrow.

The monarch also wrote that the passing of King George VI was 'so much worse' for her mother and younger sister, Margaret, to be able to look to the future.

But the young Queen Elizabeth II stoically declared 'I have a job to do' just days after ascending the throne.

In separate notes, Her Majesty expressed her delight in Charles' 'friendship' with the schoolmaster.

In fact, the young Prince Charles signed his letters to Mr Farebrother with 'Your Erstwhile Pupil' and used his nickname, 'Charlie'.

The former royal schoolmaster kept the letters and photographs in a red cloth-bound album for the rest of his life.

Aside from the snaps of young Prince Charles, the album also includes images of Princess Margaret, the Queen Mother and Her Majesty with one of her most favourite horses called Betsy.

The Queen sent a letter to Mr Farebrother on February 10, 1957, expressing her gratitude to the former schoolmaster for sending her a photo of Betsy, which she reluctantly and jokingly accepted looked more like a camel.

Her Majesty wrote: 'It was indeed kind of you to send me the photographs which you took at Sandringham and which I am delighted to have. I am only sorry that the camera proves that my dear Betsy is much more like a camel than a horse, which is what I am always being told and never believe!'

The Queen also thanked Mr Farebrother for tutoring Charles at Sandringham over the Christmas holidays of 1956/57.

'It made all the difference to him and he so obviously enjoyed you being there and it was so clever of you not to be in best 'schoolmaster-ish' with him and win his friendship so quickly,' the monarch wrote.

In a letter to his father, Mr Farebrother recounted the time he spent the New Year with the Royal family where he said that he danced with the Queen Mother.

He wrote: '...dinner with the Duchess of Glos. on my left - a film, and then hot punch and 'Auld Lang Syne' at midnight. The Queen Mum then made me dance with her to the wireless and everyone joined in. Princess Margaret puts on a rock 'n roll record and the children caper all over the place.'

The Queen also wrote personal letters to Mr Farebrother thanking him for his congratulatory notes following her engagement to Prince Philip and the birth of Prince Charles and Prince Andrew.

In a letter dated November 28, 1948 — 14 days after the birth of a 'very sweet' Prince Charles — the then Princess Elizabeth wrote: 'We are enormously proud of him.

'We are also glad that he has given a bit of happiness to so many people besides ourselves. Such a lot has happened since the Windsor days and I find it very hard to believe sometimes that I am married and have a baby of my own.'

The Queen also wrote to the former schoolmaster, 15 days after the birth of Prince Andrew.

In a letter dated March 6, 1960, the monarch wrote: 'Charles had the luck to be allowed off for the weekend - he and Anne are completely fascinated by the baby.'

There are four documents relating to the time Mr Farebrother tutored Prince Charles, including a drawing by the young prince of a rural English landscape with a house and a finger signpost and a handwriting practice where Charles had to fill in gaps of historical names and events.

Mr Farebrother attended Eton College and Oxford University where he played first-class cricket.

His career in sports was cut short by the Second World War — he served in the Grenadier Guards and fought in the Italian campaign.

Mr Farebrother worked as a schoolmaster after leaving the army and was appointed as a headmaster at St. Peter's School in 1956. He died at Seaford in September 1987 at the age of 67.

Philip Taylor, of Gorringes, said: 'We are privileged to have been instructed to offer for sale 'The Michael Farebrother Collection of Papers Concerning The Queen and her Family' which are being offered for sale for the first time. It is a unique and historically significant album of candid correspondence, hitherto unpublished photographs, and ephemera.

'It includes a large selection of manuscript letters from the Queen and Prince Charles on many matters of private and public life. Chronologically collated, the collection reflects the life and career of Michael Farebrother together with an intimate glimpse into day to day life in the Royal household in the early 1950s.'

You can find more photos and information here.