The Repair Shop's latest episode saw one guest becoming tearful after an emotional restoration was revealed to her.
Bookbinder Christopher Shaw was tasked with fixing a historic item which once belonged to a Bletchley Park code breaker.
One guest, Clare, arrived at the signature barn with a book full of codes from Britain's Second World War intelligence agency.
The item had belonged to the guest's grandmother, who had been in the Women's Royal Naval Service.
It featured recipes for puddings but was secretly stashed full of coding for Bletchley Park.
Explaining how she initially had no idea, the guest told Shaw: "I was too busy licking the spoon and stirring the pot!"
Repair Shop expert Shaw was able to take on the 'high stakes' task
BBC
The book had definitely seen better days and was crumbling and delicate, so guest Clare hoped the important item could be restored to a better state.
Impressed with the historic book, Shaw enthused: "Every page is a memory!"
He continued: "A recipe book and a spy book - I've never ever seen anything like this before.
"Operation Ginger Parkin, I think I'll call this," he went on. However, it would be a tough job keeping the book's precious significance while ensuring it wouldn't fall apart.
Clare was impressed by the final result
BBC
Shaw explained he would need to remount the book without losing any of the pages.
"I'll have to iron every single page, every single crease," he decided as he reflected on the best way to restore the item.
He later announced: "This is a hold your breath sort of moment... it's putting up a fight till the end!"
Elaborating on the process, he continued: "I'm creating a secret book underneath the original. I'm building in so much strength. What I want to do is give this to Clare and have it last for generations."
The work is second nature to the expert, but due to the value of the item, Shaw was nervous about the job.
He commented on how the restoration was "high stakes" and "high velocity".
When the all-important revelation time came, Clare was delighted with how the book had turned out.
She then reflected on her grandmother's intense work for the war effort and the secrecy surrounding it.
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The book contained Second World War codes
BBC
Sounding emotional, she explained: "She couldn't talk about anything due to the Official Secrets Act."
Host Jay Blades was equally pleased with the result and commented: "When you bake something, don't forget us!"
Blades has been making headlines recently after it was announced he and wife Lisa Marie Zbozen decide to call time on their marriage.
It was later reported Blades would be taking a break from his television duties for the foreseeable future.