BORIS Johnson’s ethics adviser has released a damning statement making clear the reasons which led him to quit the role.

Christopher Geidt stepped down as the Prime Minister’s ethics tsar on Wednesday evening in a move which the Tory leader said “came as a surprise”.

In his resignation letter, which was published on Thursday, the peer suggested that Johnson's handling of partygate and UK Government plans to extend tariffs on steel imports – which could break World Trade Organisation (WTO) rules and breach international law – had both contributed to his decision to leave.

In his letter accepting Geidt’s resignation, Johnson focused heavily on the steel tariffs question, implying that it alone had been the reason for his ethics adviser stepping down.

However, Geidt has now said that “emphasis on the steel tariffs question is a distraction”.

READ MORE: Boris Johnson 'considering scrapping ethics adviser role', Downing Street says

In a letter to Constitutional Affairs Select Committee Chair William Wragg released on Friday evening, Geidt accepted that his resignation statement may have been too "cautious".

He said the steel question was "simply one example of what might yet constitute deliberate breaches by the United Kingdom of its obligations under international law". 

The peer said that there had "been some confusion about the precise cause" of his resignation after the publication of his letter to the Prime Minister and the subsequent reply.

Geidt went on: "My letter has been interpreted to suggest that an important issue of principle was limited to some narrow and technical consideration of steel tariffs. The cautious language of my letter may have failed adequately to explain the far wider scope of my objection.

"In a BBC broadcast last night [Thursday], the former Cabinet secretary Lord Butler said the following (with my emphasis): 'He [Lord Geidt] thought it odious and impossible that he should be asked to give cover on something that might be in breach of international law and he didn't think that that was something that ought to be asked of him. This isn't about steel. It's about whether Lord Geidt should be asked to give advanced cover to the Prime Minister where there is contemplation of doing something that may be in breach of international law. When the Prime Minister is asking his own adviser to advise on the Prime Minister's conduct it really doesn't work.' 

"This represents my position precisely. Emphasis on the steel tariffs question is a distraction. It was simply one example of what might yet constitute deliberate breaches by the United Kingdom of its obligations under international law, given the Government's widely publicised openness to this."

Geidt finished by saying that he was "conscious of my own obligations under the Seven Principles of Public Life (including integrity) [and] I could not be a party to advising on any potential law-breaking".

Since Geidt quit, Downing Street has suggested that Johnson is considering scrapping the role he had filled altogether.

Reports said that the job of advising the Prime Minister on ethics would prove incredibly difficult to fill.

It took the Tory government five months to find a replacement for Johnson's previous ethics adviser, Alex Allan, who quit after his findings that Priti Patel had bullied staff were rejected by the Prime Minister.