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Prof Paul and his quantum scientists are working with Dr Margolis and her fellow researchers at NPL, who have been given the "Time Lords" nickname by other horologists.

In 1955, the NPL invented the first atomic clock of the sort that is used today, based on the frequency of radiation from an atom of the element caesium.

The NPL researchers are perfecting a so-called optical clock to achieve this, which is 100 times more accurate than the most accurate caesium clocks used today.

The NPL's immediate hope is to have a national network by 2030, connecting four atomic clocks across the UK that businesses can plug into for secure accurate timekeeping and for developing new innovative applications that harness ultra-fast time.

Yet it also noted that in some cases it was more likely to give false positive identification for black faces compared to white or Asian ones, something the NPL described as "statistically significant".