I reported a traffic light fault to TFL a couple of years ago. The
lights would only give you a green phase between midnight and 0600 if
it detected your prescence. The detector was broken so you had to go
through on red. Very carefully obviously and before you ask one night
a panda car was behind me. I explained the situation and he said i
caould go.

When I reported it they fixed it within about a week - not bad.