Today's arrest at Buckingham Palace follows a number of security alerts - last month a suspected burglar managed to get into the building after scaling a fence.
He was found at around 10.30pm on 2nd September in a room that had been open to the public during the day.
A second man was arrested outside the Palace on suspicion of conspiracy to commit burglary.
Less than 48 hours later, amid heightened security, two police officers confronted the Duke of York in the Palace gardens demanding to know who he was.
Scotland Yard issued a public apology to the Duke, which he later accepted.
More top news
Laura Schwartz, former White House aide to Bill Clinton, tells ITV News about the importance of the inauguration.
The council blames Westminster for cutting funding and say the rise is crucial to be able to afford social care.
Tom Bradby will present an ITV News special programme live from Washington DC as Donald Trump is sworn in as the 45th American President.