FTTP 37ms ping? Thought Openreach FTTP ping always get 8ms or less?
Then you thought wrongly.
The main factor is where you live. If you're in Scotland or NI then you can easily see 15ms+ ping to London.
Light in glass travels at approximately 2/3c, or about 200,000km/s. Since we're measuring round-trip times that works out at about 1ms for every 100km. But that's just the fibre propagation; it doesn't include intervening electrical devices, or that the fibre path is not in a straight line.
In this case, the poster said they are doing tests over wifi which could also add substantial latency.