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This frequency trace is generated by a live probe in London, recording at 10 Hz and transmitting on a 1 Hz cadence. The visible trace is captured in real time; the figure on this page carries a typical latency of 2–3 seconds, being the time taken to capture, store and transmit the data to this page. Benchmarked against the official frequency published by Elexon — a 15 second cadence at a latency of up to two minutes — the two agree to within about half a millihertz on average. A 1 Hz record is published by NESO, but only monthly and in arrears.