Old copies of Mills & Boon romantic novels are being used to help prolong the life of the UK's newest road.
About 45,000 books were used for every mile of motorway
In what is an unexpected twist, it has emerged that about 2,500,000 of the books were acquired during the construction of the M6 Toll.
The novels were pulped at a recycling firm in south Wales and used in the preparation of the top layer of the West Midlands motorway, according to building materials suppliers Tarmac.
The pulp which helps hold the Tarmac and asphalt in place also acts as a sound absorber and is vital in the construction of roads.
Richard Beal, the company's project manager for the M6 Toll, said the books' absorbent qualities made them a vital ingredient in the construction of the country's first pay-as-you-go motorway.
He said: "People may think they know everything they want to know about the M6 Toll, but it never ceases to amaze them when we talk about the secret ingredient that prolongs the life of this new road.
"We use copies of Mills & Boon books, not as a statement about what we think of the writing, but because it is so absorbent.
"They may be slushy to many people, but it's their 'no-slushiness' that is their attraction as far as we are concerned.
"This means that the road will last longer before we have to repair it, which is good news for the paying customers using it to escape congestion on the M6."
He said for every mile of motorway approximately 45,000 books were needed.
The books which are usually end of line or damaged are collected from across the UK and pulped at Excel Industries in Ebbw Vale, south Wales.
Tarmac spokesman Brian Kent said the company was not suggesting there was anything wrong with Mills & Boon novels.
"We want to reassure Mills & Boon readers that we're not just picking on their favourite books - other books are down there too."