Ex-Transport Secretary Chris Grayling has landed a £100,000 job advising the owner of some of the UK's top ports.
The Conservative MP is working for Hutchison Ports, which operates Harwich and Felixstowe among other terminals.
According to the MPs' register of financial interests, he will be paid for seven hours work a week for a year.
The appointment has been approved by a Whitehall watchdog despite it raising concerns of a "perceived risk" that it may give the firm an unfair advantage.
The Advisory Committee on Business Appointments (ACOBA) said Mr Grayling had reassured them he would not be advising the company on its commercial maritime activities or risks and opportunities associated with Brexit.
The watchdog said the role would be limited to advising the firm, which also operates London Thamesport, on its environmental strategy and its engagement with local enterprise bodies.
It said the MP must comply with these and other conditions, including a ban on him lobbying ministers on behalf of the company or giving advice on UK government tenders, until July 2021, two years after he left the cabinet.
Mr Grayling stepped down as transport secretary when Boris Johnson became PM in July 2019, having served under his predecessor Theresa May for three years.
Critics say he made a series of poor decisions during his time in the job, including awarding a contract to a group of ferry operators to provide extra capacity after the UK left the EU - one of which had never sailed a vessel.
The contracts, which Mr Grayling described as an insurance policy, were later cancelled. The National Audit Office estimated that the costs incurred to the taxpayer could be as high as £56.6m.
Mr Johnson sought to install Mr Grayling as chair of the powerful Commons Intelligence and Security Committee in July.
But MPs on the committee voted to back his colleague Julian Lewis instead. Mr Grayling has since quit the committee.
The MP for Epsom and Ewell is the latest former cabinet minister to get a lucrative job in the private sector while remaining in the Commons, ex-Chancellor Sajid Javid having recently been signed up as adviser by investment bank JP Morgan.
The ACOBA watchdog said Mr Javid should not take up the role until six months after he quit government in February 2020, and should not personally lobby the UK government on behalf of the bank in the two years following his exit.
'Toothless regulator'
MPs are allowed to take on second jobs - and while some have argued that representing constituents should be a full time job, others say working in "the real world" keeps members of Parliament grounded in reality.
For ex-members of the government, however, taking on paid work is slightly trickier - particularly if they have only recently given up their ministerial red boxes.
Former ministers should seek advice from ACOBA if they want to start a job less than two years after leaving their government role.
However the watchdog has often come under fire for not enforcing its rules with sufficient rigour.
In 2017, a committee of MPs described ACOBA as "a toothless regulator" and highlighted "numerous loopholes including, for example, civil servants at lower levels who have responsibility for commercial management".
And in the same year, Labour's then shadow cabinet office minister Jon Trickett said it was "populated with establishment figures".