Having just watched the episode of The Crown (Netflix series) dealing with the break in at Buckingham Palace in 1982 by unemployed man, Michael Fagan, I looked up the Wikipedia entry on the matter and was surprised to find the following:
Since Fagan's actions were, at the time, a civil wrong rather than a criminal offence, he was not charged with trespassing in the Queen's bedroom.He was charged with theft (of the wine), but the charges were dropped when he was committed for psychiatric evaluation. In late July, Fagan's mother said, "He thinks so much of the Queen. I can imagine him just wanting to simply talk and say hello and discuss his problems." He spent the next three months in a psychiatric hospital before being released on 21 January 1983.
It was not until 2007, when Buckingham Palace became a "designated site" for the purposes of section 128 of the Serious Organised Crime and Police Act 2005, that such an offence has become criminal.
Although there is no criminal law of trespass in the UK, I was always of the understanding that there was a law against "housebreaking" (or is it "breaking and entering"?) and that if it took place after dark it was a more serious offence of "burglary". Though I can well appreciate that if no goods were taken it would unlikely qualify as burglary.
But there was evidence that Fagan broke a window to get into the building, after shinning up a drainpipe - at least on the second of the two occasions.
Why would he not have been charged with "housebreaking"?