Brake lights suddenly on all time

[Yorkshire Engineer]

For no apparent reason all brake lights suddenly on all time.
Cause: foot slipped off brake pedal allowing pedal to fly up uncontrolled.
Effect: de-calibrates brake light switch.
Solution: Push brake pedal down slightly with one hand and pull stalk of brake light switch towards brake pedal until it makes contact - you will feel a ratchet-type effect.
Release brake pedal slowly. Pedal re--calibrates switch.
Background: Brake light switch slightly more clever than it seems. Stalk that makes contact with brake pedal has a friction gripper to contact operator. When fitting pull stalk fully out, brake pedal will push stalk back so that as soon as pedal is depressed contacts close.

If pedal hits stalk very quickly it can cause stalk to jump over a detent resulting in the switch thinking that pedal has been depressed. Can also be de-calibrated during valeting carpets.

You may need to slide driver's seat right back or even remove it to make room for your shoulders - very awkward location high up in driver's foot well.