Please do not say or write "Mr Foo Bar" on first mention - just say "Foo Bar" the first time you refer to a person - after that, you can call him "Mr Bar". The Economist's Style Guide spells it out nicely. In fact, the "Mr Foo Bar" form is not proper at all, but is sadly used almost universally by (at least) English speaking Indians - just use the surnames with "Mr/Mrs/Miss" as in "Mr Bar". This is not to say that I speak/write perfect English (I strive to, but mostly fail), but there are some things that irritate me more than others and this is one of them.