MPs have topped up their salaries by a staggering £17.1million since the last general election, a new analysis claims.
The vast majority of outside earnings - over £15million - went to Tory MPs and around two-thirds of the total went to just 20 MPs.
Ex-PM Theresa May came out on the top of the list, raking in over £2.5million with her biggest payments coming from speaking engagements.
All the sums have been previously declared on Parliament’s register of members’ interests - but have now been brought together under one database.
Drawn up by Sky News and Tortoise Media, the Westminster Accounts show that 17 out of 20 MPs with the biggest outside earnings are Conservatives.
They include Mrs May and Boris Johnson, who has also earned tens of thousands from speeches since he was removed from No10 in July 2022.
The Tory MP Sir Geoffrey Cox is the second highest paid for work outside Parliament and received over £2.1million from different law firms.
In a statement, he told Sky News there was "no conflict of interest" between his role as an MP and his work as a barrister.
"On the other hand, I frequently put my experience and understanding of the law at the service of my constituents in helping them to resolve their individual problems in my regular advice surgeries," he added.
Just two Labour MPs - David Lammy and Jess Phillips - feature in the top 20 MPs with the largest earnings outside Parliament.
The Shadow Foreign Secretary Mr Lammy, who received more than £87,000 for his work hosting a show on LBC radio, has previously defended his work.
He told listeners in 2021: "Why am I here? Why am I pleased to be here? One because I am the only black presenter on LBC.
"It's important for my constituents - I love the fact they approach me and can hear me putting views that they agree with out there into the public."
Speaking on Sky News Sophy Ridge on Sunday programme, the Labour leader Mr Starmer said "transparency is a good thing".
He has previously called for a ban on MPs' second job - but suggested media work such as Mr Lammy's could be grounds for an exemption.