Most people in Bolton will at some point in their lives have travelled along the A666, also known as the “devil’s highway”. 

The road forms the spine of the town, running from Egerton in the north where it is Blackburn Road, all the way through the town centre and out through Kearsley, joining East Lancashire and Salford. 

From the town centre onwards, the road becomes a dual carriageway, commonly known as St Peter’s Way, splitting the centre, Great Lever and Farnworth from the eastern reaches of the borough.

At the end of the dual carriageway, it is signposted as becoming the M61 - however, at this point the road has something of a dual identity. 

Google Maps labels the road as the "A666(M)", as have road maps from the early 1970s. 

St Peter's WaySt Peter's Way (Image: Newsquest)

However, there are no road signs or markings that refer to it as such and there is no legislation which refers to any such road, with other sources calling it the M61 instead. 

Bryn Buck, from Bolton, designs highways for a living, including roads, cycling schemes and walking schemes. 

Bryn is particularly "enthusiastic" about the industry - when he was five years old, he went to school for World Book Day dressed as the Highway Code. 

The Bolton News asked him about the town's mystery motorway.

He said: "It is one of those things I have been trying to get to the bottom of for a long time. 

"A few months ago someone crashed a car down there, it took out a bit of the railings and some of the wall at the exit slip for Kearsley. 

Bryn Buck]Bryn Buck (Image: Public)

"I was going to work one morning and it hadn't been cleaned up after the incident." 

Bryn, who is originally from Darwen, runs a YouTube channel which shares his name, making videos about roads and transport. It can be seen here: https://www.youtube.com/@BrynBuck

He added: "I had an inkling of uncertainty with the road number. When it first opened, maps from the 1970s listed it as being the A666(M). 

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"But I have never found any government legislation that backs that up. 

"I rang up National Highways for the motorway section and quoted the mileage number to them." 

Google Maps shows the road as being called the A666(M)Google Maps shows the road as being called the A666(M) (Image: Google Maps)

But Bryn said the operator "didn't have a clue" where he was referring to, instead finding it on Google Maps as the A666(M). 

He said: "I don't know how it appeared on Google Maps because they usually cross reference with official sources, so if it appeared there then someone must have told them. 

"It has become one of those weird mysteries. 

"Directions on signs are meant to make it simple. If you're coming out of Bolton, it doesn't actually help to say 'A666(M)', you have two options, going onto the M60 or the East Lancashire Road. 

"It is one of those 'I bet you didn't know this' throwaway things you might say when you're having a chat with someone in the pub."