A recipe book has been returned to a library more than 50 years after it was due back.

It was posted to Paisley Central Library anonymously along with a £20 note and a letter apologising for it being so long overdue.

The book, Mrs Balbir Singh’s Indian Cookery, is thought to have been loaned out around 1968 but there is no way of knowing who borrowed it or exactly when because it was before records were digitised.

The letter accompanying the returned book, published by Mills & Boon in 1965, said: “Please accept my apologies for the late return of this book.

“Enclosed is a token payment in recognition of this oversight. Thank you.”

The £20 will be donated to charity as Renfrewshire Libraries is currently not imposing fines for the return of overdue books.

Linda Flynn, Paisley Central Library team supervisor, said: “I was more than a little surprised when I opened the padded envelope and saw what was inside.

“It’s rare to have a book returned after being overdue for so many years. I suspect the book had been lying in a cupboard or a drawer for some time and was only recently discovered.

“It was a lovely gesture from whoever found the book to take the time to send it back with a £20 note as a token gesture for it being so long overdue. We’ll make sure the money goes to a good cause.”

She added: “You could see that the book had been well used and some of the marks on the pages suggested that someone had followed the recipes to make a good few dinners.

“Unfortunately, the book isn’t in a condition to put back on our shelves for people to borrow, but, since it’s become a talking point among library staff, we’ll keep it in a safe place.”

Mrs Balbir Singh was born in the Punjab in 1912 and became an internationally renowned chef, cookery teacher and cookbook author.

Her Indian cookery book met with acclaim when it was first published in London in 1961, and went on to inspire future generations of chefs and home cooks.

It sold hundreds of thousands of copies worldwide and several editions with revisions and extra recipes were printed in subsequent years.

Mrs Balbir Singh died in 1994.