More than one in eight MPs are still using a loophole to employ a member of their family using taxpayer money.
MPs were banned from using public cash to hire family members, also known as "connected parties", in 2017 after it emerged around one in five MPs - more than 120 - were hiring family members and paying them from the public purse.
The Independent Parliamentary Standards Authority (IPSA) now states that MPs cannot claim expenses for goods, services, or property for people who are "connected parties", which includes spouses, partners, children, parents, and siblings.
Watch: Owen Paterson: Cabinet minister Nadhim Zahawi admits 'mistake' in saving Tory MP from suspension while rewriting standards rules
However, the ban did not apply to those employed before 9 June 2017. This means that any MP employing a family member now who was hired before this date is not breaking any rules.
IPSA at the time said the practice of MPs employing family members was "out of step" with modern employment practices.
Among MPs currently employing family members are 41 Conservative MPs who employ their wives, largely as office managers or secretaries.
Overall, 87 MPs had family members working for them in the current session – accounting for just over 13% – holding roles including caseworkers, parliamentary assistants, and office managers.
Several high-profile MPs are among those claiming expenses for their wives who are working for them, including: Scottish National Party (SNP) leader Ian Blackford; Tory MP and former justice secretary Robert Buckland; Tory MP Johnny Mercer; and former cabinet minister and Labour MP Hilary Benn.
The analysis comes amid fresh scrutiny of MPs over their second jobs, raising fears some are not prioritising their work as MPs as well as creating potential conflicts of interest.
Attention to the issue was sparked after the government attempted to prevent the 30-day suspension of Conservative MP Owen Paterson, who was found by IPSA to have committed an "egregious" breach of lobbying rules.
The government attempted to change the parliamentary standards watchdog by replacing it with a committee of MPs that would have a Conservative majority, but Boris Johnson was forced into a humbling U-turn after opposition parties boycotted it.
Since then, the conduct of other MPs has come under intense scrutiny, including the behaviour of former attorney general, Sir Geoffrey Cox.
Cox has come under fire after it emerged he stands to make more than £1m representing the British Virgin Islands at an inquiry set up by UK government into corruption and money laundering in the country, as well as continuing to earn his annual MP salary of almost £82,000.
It has also emerged that he rented out a taxpayer-funded London flat while claiming £1,900 per month for a second home, as well as missing four Commons votes to go on an overseas work trip to Mauritius this week.
The former attorney general has defended himself from criticism, claiming he received permission to work from the Caribbean from the Conservative whips office.
Elsewhere former work and pensions secretary, Tory MP Sir Iain Duncan Smith, has also come under fire for receiving £25,000 as an advisor to hand sanitiser company while chairing a government task force where recommendations by him would have benefited the company.
Other MPs receiving huge sums of money alongside their MPs salaries include former Tory prime minister Theresa May, who has raked in over £700,000 since the start of the pandemic giving speeches - and current health secretary Sajid Javid, who brought in over £300,000 doing work for financial companies such as JP Morgan Chase.
Boris Johnson was forced to state that the UK was not a corrupt country in front of the international media at COP26 in Glasgow on Wednesday after he was challenged by journalists over the growing "Tory sleaze" allegations.
"I genuinely believe that the UK is not remotely a corrupt country and I genuinely think that our institutions are not corrupt," he told the conference.
"We have a very, very tough system of parliamentary democracy and scrutiny, not least by the media.
"I think what you have got is cases where, sadly, MPs have broken the rules in the past, may be guilty of breaking the rules today. What I want to see is them facing appropriate sanctions."
Watch: Who is Sir Geoffrey Cox?