A previously unpublished letter from JRR Tolkien, in which the author of The Hobbit and The Lord of the Rings describes teaching as an “exhausting and depressing” profession, is expected to fetch up to £2,000 at auction.

The letter, signed by the author, was rediscovered by a retired English teacher, after it had been hidden inside a book for almost half a century. It will be sold by auction house Bonhams, on 19 June.

Anne Mountfield was a recently qualified teacher, working in a south-London comprehensive in 1963. Struggling to engage her class of restless 13-year-olds, she read them Tolkien’s novel, The Hobbit.

Her students loved the book. Mrs Mountfield therefore suggested that they write letters to Tolkien, explaining why they had enjoyed it. She sent the best letter to the author, along with a covering letter in which she thanked him for his class-silencing novel.

In January 1964, she received a typed letter in return. It read: “The Hobbit seems to go down well at school; I have had several letters telling me of class activities arising from interest in it. Not all as well penned as this.”

“The children were quite excited,” Mrs Mountfield said, looking back. “It made them realise that authors are people, and actually exist and write back to you.

“Tolkien wasn’t a very, very big figure in the early 1960s. He was a children’s author of some note, but I don’t think he was anything like the mega figure he is today.”

In a handwritten addendum to the letter, which Mrs Mountfield did not read out to her students, Tolkien wrote: “All teaching is exhausting and depressing and one is seldom comforted by knowing when one has had some effect.”  

Tolkien had been a teacher himself, and it was while correcting exam papers that he scrawled on a blank sheet of paper: “In a hole in the ground there lived a hobbit.” This became the opening line of his novel.

Mrs Mountfield put the letter inside a book, and promptly forgot about it. “If you’d said, ‘Do you have a letter from Tolkien?’, I’d have said, ‘Yes’,” she said. “But I’d have had no idea where it was.”

But then, when Mrs Mountfield was clearing out her bookshelves last year, the letter fell from its hiding place. “I thought it would be better with someone who loved it, rather than stuck on a book on my shelf,” she said.

She took it to Bonhams to be valued, and subsequently put it up for auction. It is expected to fetch between £1,500 and £2,000.

“A lot of Tolkien letters come on the market,” said Simon Roberts, senior valuer in Bonhams’ books and manuscripts department. “What’s nice about this one is the story behind it. ‘Exhausting and depressing’ is obviously going to resonate with a lot of people in the teaching profession.”