Motorway gantry sign
A gantry spanning the motorway with blue overhead signs showing the following text.
Forward destinations: The NORTH, Peterborough A1(M).
Exit destinations: B1043 Sawtry, Ramsey (B660).
Junction number: 15.
This is junction 15 because the motorway bits of the A1 were all assigned junction numbers as though the gaps had been filled in. Junctions 11 to 13 don't exist and probably never will.