Speaking to reporters at the COP26 summit in Glasgow, Johnson said that he would not comment on individual cases, but underscored that "the rules say two crucial things: you must put your job as an MP first and you must devote yourself primarily and above all to your constituents and the people who send you to Westminster, to parliament".
"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", he reiterated.
He spoke after Labour Deputy Leader Angela Rayner urged him to explain "why he thinks it is justified for one of his MPs to be paid by a company that stands to benefit from a recommendation of a task force chaired by that same MP".