A book bought for a fiver two decades ago is expected to fetch as much as £20,000 at auction.

Sarah Hickman, from Faversham, purchased the original 17th century volume at a bookshop and says she had no idea just how valuable the item was.

She picked up the copy at a shop in Richmond almost 20-years-ago and now cannot believe her luck.

The book, titled England’s Treasure by Forraign Trade and dating back to 1664, goes up for auction at Christies in London next Wednesday.

It was written by Thomas Mun, a prolific trader and former director of the East India Company, the company established by the Crown which helped expand British trade across the world.

Miss Hickman says she had completely forgotten about the book and only came across it while she was tidying up her collection.

She said: “Rather than running my finger along the shelf and just touching the spine, I was getting them out and it was in a stack of old books.

“My partner said ‘this one’s an old one’ and I Googled it.”

Miss Hickman found one version of the book had been sold at auction in London for about £3,500 three years ago and so she emailed Christies to find out more about it.

“About three minutes later they replied and said it was interesting,” Miss Hickman added. “He said it’s worth at least £12,000 but would like to have a look and when could I come up.

So I said ‘how about tomorrow?’.

The listing by Christies describes the book as a “very rare first edition” which has not been recorded at auction since 1977.

It was written in 1628 but not published until 1664, three years after Mun’s death.

“It’s a little bit of magic, everyone hopes this happens to them,” Miss Hickman added.

“I was extremely pleasantly surprised and lucky to have bought it, because I loved it, but also for it to be valuable.

“Having studied printing I knew it was an original and in good condition and it was a handsome book. It’s always been a reasonably valuable book but the seller didn’t know how lucky for me.”

Miss Hickman says it is a “truly Kentish book” as it was published in Bearsted near Maidstone.

The book is listed with a guide price of £15,000 to £20,000, with a £12,000 reserve.

“There’s an awful lot of interest because a first edition hasn’t come up for 35 years,” Miss Hickman added.

She hopes to invest the money into her business, Hixx - a company providing all natural dog products such as toys and beds.

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