Sadly no, I assume you actually mean calabrese as purple sprouting broccoli should not be anywhere near ready. You don't say where you are in the UK but if your are in the south where it was very hot and very dry for almost all of the spring the plants have gone in stress, panic mode. So rather than producing a head of immature flowers they've gone straight into full flowering mode to set seed. A lot of folk have commented on this and we have brassicas, including milan turnip, which are flowering this is unusual as all brassicas are biennials.

The broccoli you eat is actually the flower buds, so when the yellow flowers appear it is too late.