A newly discovered letter by English writer and ‘father of the modern dictionary’ Dr Samuel Johnson has sold for £38,460 at auction.

Gloucestershire-based auctioneers Chorley’s had estimated the letter was worth at least £8,000 before it was sold on Wednesday.

Dr Johnson wrote the Dictionary of the English Language – containing 40,000 words – in 1755 and was also a playwright, poet and literary critic.

The Oxford Dictionary of National Biography refers to him as “arguably the most distinguished man of letters in English history”.

Samuel Johnson's charming letter to a young Sophia Thrale will remain in the UK and we hope it will be displayed to the UK public in time

The item had been found stashed among a number of historic letters in a cupboard in a Gloucestershire country house during a routine valuation by Chorley’s specialists.

British and American museums bid for the letter, before it was eventually won by a British buyer.

The letter was written to 12-year-old Sophia Thrale, the daughter of British author Hester Lynch Thrale.

In it, Dr Johnson praises Sophia’s maths skills and tells her she will always have his favour.

A group of letters found at the same property were also auctioned by Chorley’s for £98,000. They had been estimated at £15,000-£20,000.

Chorley’s director Werner Freundel, said: “We are thrilled to have brought the Hester Thrale correspondence to light and are pleased that the historical importance of the letters has been recognised.

“Samuel Johnson’s charming letter to a young Sophia Thrale will remain in the UK and we hope it will be displayed to the UK public in time.”

The writer died in 1784 and is buried in Poets’ Corner in Westminster Abbey.