A Conservative MP has been told to apologise for breaching rules on donations.
David Morris was found to have broken the paid advocacy rule when he asked a question in the Commons after accepting a £10,000 donation.
Parliament's Standards Commissioner also criticised Mr Morris's conduct during her investigation into the case.
Mr Morris will need to make a formal apology in the House of Commons.
MPs are not allowed to lobby for any person or organisation within six months of receiving any money from them as a donation.
Lobbying means trying to get support on any topic of interest, by asking parliamentary questions, approaching Ministers, public officials or other MPs.
The Commissioner, Kathryn Stone, considered the circumstances surrounding a question Mr Morris asked in the Commons on 22 October 2019.
In September 2019, Mr Morris had accepted a donation of £10,000 from Aquind Ltd, which was declared on his register of interests.
The firm is led by Ukrainian-born businessman Alexander Temerko, who is now a British citizen. Mr Termerko has donated more than £1m in total to the Conservative Party, and individual Tory MPs, in recent years.
Mr Morris's question sought for Ofgem - the energy watchdog - to "protect" companies such as Aquind Ltd through new regulations.
The following day, Mr Morris also emailed a copy of his question and the minister's reply to the Secretary of State for Business Energy and Industrial Strategy.
The commissioner found that the question and the email breached the rules on MPs conduct.
The commissioner accepted that Mr Morris's rule breaking was inadvertent, but criticised his behaviour during her investigation as "regrettable and disrespectful of the House's system of standards".
The report on the case said Mr Morris also "repeatedly questioned the commissioner's remit and her right to consult her officials".
But it added, "Mr Morris subsequently apologised to the commissioner and the Registrar and outlined factors he considered had influenced how he had engaged with the investigation."
The commissioner also noted that she understood him to be "deeply apologetic and remorseful for the tone adopted" in some of his correspondence, and that "no disrespect had been intended to me or my office."
Sanctioning the MP for breaking the rules, the Committee on Standards noted that Mr Morris had "acknowledged he had breached the rules and apologised" and recognised that Mr Morris "had been dealing with particularly challenging and stressful personal circumstances which may have affected his judgment and behaviour during the investigation".
The committee added: "Any breach of the paid advocacy rule must always be regarded as a serious matter.
"Mr Morris should apologise to the House by means of a personal statement, which should be agreed in advance with Mr Speaker and the Chair of the Committee."