The army marching band (Coldstream Guards?) was playing the Darth Vadar Evil Empire "Imperial March" theme from Star Wars just as King Abdullah pulled up in his limo to greet the Queen.
What the fuck!!! Is this a jibe by the army (or rather HM Liz) at the Saudis?
Let's hope so, although I think that I detect the hand of the D of E, frankly. Whatever: as Not A Sheep points out...
As Wikipedia says "The theme...represents the totalitarian Galactic Empire as a whole, and Darth Vader specifically. More than other Star Wars themes, the March has attained an iconic status in the Western consciousness as a general "evil theme", and as such is used to portray power at public events".
Since just about all music and film seems to be banned in Saudi, King Abdullah almost certainly does not know what the music is. Ha!
UPDATE: it's here! Only about the first 20 seconds, alas...