A new road sign at Watford Gap, in Daventry, Northamptonshire, has been unveiled as part of the celebrations of the M1's 50th anniversary.
The new sign, which has one arrow pointing north and another pointing south, only confirms the popular idea of the service station being an unofficial dividing point between Britain's north and south.
RoadChef, which operates the services, said the firm has erected the sign as a tourist attraction next to which people could pose for photos.
A spokeswoman said: "Because of the anniversary, we're looking at what Watford Gap means to everyone."
The company is working towards getting "Watford Gap" included in the Oxford English Dictionary as a recognised term expressing the division between north and south.
The services, which houses a Costa coffee shop, a Wimpy burger bar, a RestBite restaurant and a WH Smith newsagent, has had many celebrity customers over the years.
It is said that singer Jimi Hendrix mistook it for a London nightclub as it was mentioned so often by his contemporaries.
The service station was previously called the Blue Boar.
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