In theory I would agree with you, OPD. However, there are a number of immigrants who have lived in the UK for years who do not speak a word of English (granny's, 2nd cousin twice removed etc.) who can't speak a word of English and will never learn because the family translate for them and they don't want to learn the language.
I, personally, am a great fan of the Australians stance on this - if you don't like our language, customs, laws etc, then go home. we didn't invite you, you came of your own free will, bog off if you don't like it.
Even if you have a smattering of Turkish (which I do and I make use of) the passport police ARE obnoxious, bloody rude and incompetent. Especially the Sergeant if he's still there.
And before we down the road of 'they're not paid much' etc. etc. that is no excuse. NO civil servants are paid much. Perhaps if they did their job more efficiently and with a smile they would get promoted.