This weekend Red Lion Books in Colchester's High Street will mark the occasion with a special, sold-out, classical concert at the Pimlott Foundation in Great Horkesley.

In a time when the independent High Street store is coming under ever increasing pressure from chains and the internet, Sarah and Peter Donaldson shine a bright light for book lovers and indie shops alike.

But it might have been very different if the couple had decided on a different career path.

Peter says: "It was a choice of running an independent book shop or becoming organic market gardeners and after we got all the pamphlets from the Department of Agriculture and started waded through them, we thought books were for us."

Moving from Bath to Colchester, where Sarah had family connections, they opened up their first shop in the old stables of the Red Lion Hotel, across from where they are now.

It was in 1986, the pair moved to where they are now on the High Street.

"We needed more space for stock," Peter says.

Sarah adds: "I think being on the High Street has been very beneficial for us, especially being next to Mann's Music. Book people like music and music people tend to like books."

This Sunday's concert will include classical pieces which have been matched with some of Sarah and Peter's favourite books.

It's a rather novel way to celebrate 40 years but then Red Lion has always been a unique shop for its special events hosting signings by the likes of Terry Pratchett and Game of Thrones writer George R R Martin.

Peter says: "Terry Pratchett became a good friend of the shop after we asked him along quite early in his career and I remember George Martin telling us that his books were just about to be filmed, so we got him just at the right time."

Forty Years in Four Books

Each Peach Pear Plum by Janet and Alan Ahlberg

Published just as we opened our doors for the first time 40 years ago. Our children loved it and more recently our grandchildren.

Mort by Terry Pratchett

Terry Pratchett's regular visits to the shop over 20 years attracted ever increasing numbers of fans until the queue would stretch out of our door and up the High Street to the Town Hall.

Harry Potter and the Deathly Hallows by JK Rowling

Our launch parties for the Harry Potter series grew with every new episode until for the last book we mounted our biggest ever event, taking over Colchester Castle and turning it into Hogwarts for the midnight release with 300 people.

The Essex Serpent by Sarah Perry

With scenes taking place a few yards from the shop’s front door and with such rich characters and themes it is no surprise that this has been our biggest selling new novel for many years.