Lights turn off cruise control

[hamondo]

yesterday i went to wales and back, going there the cruise was working fine, on the way back it was getting dark so switched lights on while cruise was on soon as lights came on cruise went off, I know other members have had the exact same probs.(Geordie George also has the same issue), any info welcomed.

I have checked and removed rear tow electrics to eliminate.
I have checked and removed front spot lamps to eliminate.
I have checked earthing from cruise control unit is good.

As the cruise works fine without lights on it would maybe suggest that when the side lights go on some form of signal from the light wiring is interfering with the cruise control unit?