Let's compare US prices to UK before taxes.
So, $999 is £751 (at a 1.33 middle exchange rate)
£751 + 20% VAT is £901.
Still a large-ish profit for Apple in the UK, but not as big as it seems.
You can blame the British government for upping the VAT rate in 2011 for some of the UK price (about £20 difference between the two VAT rates).