<a href="https://www.thenationalnews.com/tags/liz-truss/" target="_blank">UK Prime Minister Liz Truss’s</a> office said on Tuesday there was nothing unusual about her chief of staff failing to accompany her on a trip to New York, after he was linked to a bribery investigation by the FBI. Mark Fullbrook stayed behind as <a href="https://www.thenationalnews.com/world/uk-news/2022/09/19/uks-liz-truss-visits-new-york-for-meetings-with-world-leaders/" target="_blank">Ms Truss travelled to the UN General Assembly</a>, where she will meet leaders including <a href="https://www.thenationalnews.com/tags/joe-biden/" target="_blank">US President Joe Biden</a> on her first foreign trip since taking office. The prime minister’s spokesman said Mr Fullbrook “has her full support” and put his absence down to the volume of government business, as day-to-day politics resumes after <a href="https://www.thenationalnews.com/world/uk-news/2022/09/08/queen-elizabeth-ii-dies-latest-news/?page=12&post=1213914177" target="_blank">the royal mourning period</a>. “It's actually not unusual for the chiefs of staff to remain in Downing Street during these trips,” the spokesman said. “There's a lot of government business taking place this week. If anything, it's more unusual for them to attend and not remain in Downing Street to oversee that work.” <i>The Sunday Times </i>reported at the weekend that Mr Fullbrook had been interviewed by detectives in connection with a political scandal in Puerto Rico, a US territory. He denies any wrongdoing. The island’s former governor Wanda Vazquez Garced was charged last month with accepting a bribery offer from bankers during an election campaign in 2020. Prosecutors allege that the scheme involved paying the political consultancy CT Group, where Mr Fullbrook was a senior executive, to support Ms Vasquez Garced’s re-election bid. US detectives spoke to Mr Fullbrook and agreed that his testimony would not be used against him, according to <i>The Sunday Times</i>, which said he was co-operating as a witness. A spokesman for Mr Fullbrook told the newspaper that he was “committed to and complies with all laws and regulations in any jurisdiction in which he works and is confident he has done so in this matter”. Mr Fullbrook, who left CT Group to start his own company in April, was named Downing Street chief of staff two weeks ago when Ms Truss was appointed prime minister. The prime minister's spokesman said on Tuesday that Ms Truss stood 100 per cent behind her appointment of Mr Fullbrook. A veteran of Conservative election campaigns, Mr Fullbrook ran <a href="https://www.thenationalnews.com/tags/boris-johnson/" target="_blank">Boris Johnson’s</a> winning leadership bid in 2019 and has worked with prominent Australian adviser Sir Lynton Crosby. He is rumoured to have ordered a strict dress code for aides after unprofessional behaviour at Downing Street contributed to Mr Johnson’s downfall. Ms Truss has promised to restore trust after a series of scandals.