John Williamson wrote:
The time reference point is the end of the last pip. Technically, the

No, it's the start of the last pip.

Each pip starts at the x.00 second point, at 55.00, 56.00, 57.00,
58.00, 59.00 and 00.00. The first five five are 0.1s long, the last
is 0.5s long. The reference point is the start of each pip.

The pips are calibrated so that they are UTC accurate 160km from
the London transmitter so averaging out the light-speed lag
across thr country.

JGH