What is the longest distance between junctions on a british motorway?

Question

What is the longest distance between junctions on a british motorway?

Answer 1

The longest distance is westbound on the M26 from junction 2A. The next interchange is with the M25, but exiting there is not possible in this direction. The next exit from the motorway is some 18 miles later at M25 junction 6. Signs on the M26 warn of this.

Answer 2

possibly on M11

Answer 3

i think the longest one on the M1 is from Milton Keynes Junction 14 to Northampton Junction 15.

its about 14 miles.