You don't have to look that hard to find that this is not true.
Boris Johnson (the UK Prime Minister) was a US citizen until sometime in 2016. His UK political office roles until then included serving as a MP (2000-2008), Mayor of London (2008 - 2016), and UK Foreign Secretary (2016 - the time he relinquished his US citizenship). Reports indicate that he gave up his US citizenship to avoid the IRS taxing him.
Boris Johnson (the UK Prime Minister) was a US citizen until sometime in 2016. His UK political office roles until then included serving as a MP (2000-2008), Mayor of London (2008 - 2016), and UK Foreign Secretary (2016 - the time he relinquished his US citizenship). Reports indicate that he gave up his US citizenship to avoid the IRS taxing him.