Why was a hotel suite in London part of Yugoslavia for just one day in 1945?

After the First World War, Claridge's flourished due to demand from aristocrats who no longer maintained a London house, and an extension was built in the 1920s. Peter II of Yugoslavia and his wife spent much of the Second World War in exile at Claridge's, and suite 212 was ceded by the United Kingdom to Yugoslavia for a single day (June 17, 1945) to allow their heir, Crown Prince Alexander, to be born on Yugoslav soil.[1]

Good one Fred.

The topic came from QI (for 'Quite Interesting'), a comedy trivia quiz with teams of comedians hosted by Stephen Fry, where the questions are amusingly eccentric and obscure and the answers followed by some exposition ( usually interrupted by irreverent commentary from the teams). Sample: 'Who first put two feet on Mount Everest?' Answer : The first man to attempt to measure it properly. He measured it by theodolite and got the height as 29,000 feet 'exactly'. Thinking that this would seem to be an approximation and not a true reflection of his 'accuracy' he added two feet to his figure and published it as 29,0002!' Exposition included 'Everest is not Everest: That is, we say Ever-Est. The Surveyor-General of India, George Everest, whose name was given to it, pronounced his surname 'Eve-Rest'' Hope the format makes it to the US

By the way, the Wiki answer has the wrong month. The Crown Prince was born on July 17th, not June 17th

Right about the date of birth. In fact when you click on his name (Alexander) it opens up another page which clearly says July 17th.