Government officials were warned repeatedly about making misleading claims about job figures before the official statistics watchdog reprimanded Boris Johnson over the matter. Ed Humpherson, the director general of the UK Statistics Authority (UKSA), said there had been “a series of informal discussions” before the regulator took the “unusual” step of issuing public rebukes to No 10 over the same issue twice last month. During more than half a dozen editions of prime minister’s questions since November, Johnson has made the misleading claim that more people are in employment in the UK than before the pandemic began. Yet, although the numbers of workers on payrolls has risen, the number of self-employed people has dropped significantly so that the total number of people in work is down by 600,000. The chair of the UKSA, Sir David Norgrove, wrote to Johnson saying he was making “a selective use of data” and added that “public trust requires a complete statement”. A few weeks earlier, Humpherson had written about the same matter to Laura Gilbert, Downing St’s chief analyst, saying the use of payroll figures was “disappointing”. “This is not something we do lightly – we don’t have an objective to get a certain amount of column inches,” Humpherson told the Observer. “And this is not an intervention at a personal level. We are clarifying the correct interpretation of those statistics. In a sense, we’re on the side of the statistics. We are not a referee in the debate. “I had written to the head of data science in No 10 about this issue. And that itself followed a series of informal discussions where we said ‘we think you need to look again at how these numbers are being referred to’.” Humpherson said politicians and civil servants usually respond well to interventions by the statistics watchdog. “We don’t have to do this very often because by and large politicians and the people who brief politicians try really hard to get it right. And the general experience is that when they don’t quite get it right, they welcome the clarification that we provide.” But he conceded that the fact that the UKSA had written repeatedly to the prime minister about his use of employment figures was unusual. “It’s unusual. We had to write twice to Matt Hancock about testing data in May and early June 2020,” Humperhson said. “It is unusual, but not without precedent.”Humpherson welcomed the declaration on government reform that the prime minister and the cabinet secretary made last year, to build greater expertise in government on data. “It was really strong on the role of data, the role of analysis and the role of validation. That’s brilliant,” he said. Referring to initiatives such as the coronavirus dashboard, he said: “The data revolution within government has been happening over time, but the pandemic really accelerated that.” He said there was a recognition that data was more useful when it was linked together from several sources, and the Office for National Statistics’s new Integrated Data Service was doing this across government. “The risk is that the data stays close to the chest,” he said. “And actually what the pandemic shows is that there is a public appetite to make it available.”