More than a quarter of Tory MPs have second jobs with firms whose activities range from gambling to private healthcare, making more than £4m in extra earnings in a year, Guardian analysis has found. The register of MPs’ interests shows that more than 90 out of 360 Tories have extra jobs on top of their work in parliament, compared with three from Labour. They are overwhelmingly older and 86% are men. The highest earners were all former cabinet ministers. The row over sleaze, including “egregious lobbying” by the veteran backbencher Owen Paterson on behalf of companies that paid him over £100,000 a year, has focused attention on moonlighting by MPs. On Monday Steve Barclay, the Cabinet Office minister, rejected the idea of banning second jobs, saying it could stop some MPs getting experience of the outside world. They must understand, however, that “in performing their parliamentary duties they are expected to act in the public interest”, he said. The highest earner is Andrew Mitchell, the MP for Sutton Coldfield, who made £182,600 for 34.5 days’ work in a variety of financial advisory roles, with firms including Investec and EY. Geoffrey Cox, the former attorney general, is making around £1m a year as a barrister, while Chris Grayling, the former transport secretary, is earning £100,000 a year from Hutchison Ports Europe, the register shows. John Redwood, a former Welsh secretary, is earning more than £230,000 working for an investment advisory company, Charles Stanley, and a private equity firm, while Alun Cairns, a former Welsh secretary, acts as adviser to a Wales-based global diagnostics company, BBI, with all his consultancy roles bringing in a total of £60,000. Liam Fox, a former trade secretary, has a £10,000 contract with WorldPR, a Panama-based PR company for advice on business and international politics, while Julian Smith, the former chief whip, is making about £144,000 a year from advisory roles with marine, renewables and hydrogen firms. Although ministers are not supposed to have second jobs, some have managed to hold on to them in currently unpaid capacities. Jacob Rees-Mogg, the leader of the House of Commons, remains an unpaid partner in Somerset Capital Management LLP, an investment management firm. Alister Jack, the Scottish secretary, is also still an unpaid director of Atlantic Solway Holdings, an investment company in the sport fishing sector. Two Tories have jobs linked to the gambling industry: Laurence Robertson, Tory MP for Tewkesbury, gets £24,000 a year to be a parliamentary adviser to the Betting and Gaming Council, while Philip Davies, the MP for Shipley, is paid £16,660 by GVC Holdings, owner of Coral and Ladbrokes, plus £12,000 a year by the National Pawnbroking Association. The Guardian reported on Sunday that more than 30 MPs have jobs that could be considered direct political consultancy, which could face a clampdown. However, dozens more have lucrative board seats and advisory council jobs that are likely to involve giving political advice. Some are also earning money through personal service companies, an arrangement that can help lower their tax bills. Paterson, the MP for North Shropshire, resigned following a furore over his lobbying rule-breaking and attempts by the prime minister to halt his 30-day suspension, which ended in a U-turn. MPs are banned from direct lobbying, but there are various loopholes, including being able to provide political advice to firms without carrying out advocacy themselves. In contrast to the high number of Tories with second jobs, few opposition party MPs moonlight. Among Labour MPs, Rosena Allin-Khan earns extra income as a doctor, Margaret Hodge has a £20,000-a-year role at Royal Holloway University and Khalid Mahmood has a £25,000 advisory job at the Policy Exchange thinktank. The analysis includes those with company directorships even if they are not directly salaried, but not those with unpaid roles at charities or thinktanks. It also did not count those who receive ad hoc payments for journalism, speaking at events, training, lectures or surveys – even though this is substantial additional income often earned as a result of an MP’s parliamentary position. It comes as research from Savanta ComRes found that almost half of UK adults oppose MPs being allowed to have a second job alongside their role in parliament, with just one in five supporting it. Labour proposed banning second jobs for MPs at the last election, although Starmer has stopped slightly short of endorsing that position. But Richard Burgon, formerly the shadow justice secretary, is tabling a new private member’s bill to parliament that would ban all second jobs, with limited exceptions for professional MPs such as nurses and doctors to carry on their work. Burgon said MPs should not be “lining their pockets by moonlighting in other roles – and it is especially outrageous that this was happening during a public health crisis”. “The job of being an MP is not only a great privilege, but it is also well paid, and it should be the full focus of anyone lucky enough to be elected as an MP. If people want to seek lucrative roles elsewhere, then no one is stopping them, but they should step down as MPs to do so,” he said. “My bill will put an end to this racket by banning MPs from having second jobs, except in limited exceptions, for example, where nurses need to work to maintain professional registrations or so a doctor can carry on serving our NHS.” • This article was amended on 9 November 2021. Geoffrey Cox is making around £1m a year as a barrister, not £1.6m as an earlier version said. This has been corrected, and as a result the overall figure given in the text for extra earnings in a year has also been revised to a total of “more than £4m”, rather than “about £5m” as previously stated. The headline has also been updated to reflect this change.