The US price is pre-tax (depends on state: 8.5% in California). The UK price, like most other countries in the world, already includes all taxes (VAT is 20%). In California the $1299 MBP will actually cost you $1414 including sales tax, a difference of just $117. In the UK the price includes AppleCare (under EU law), which would cost an extra $249 in the US. So if you were going to buy AppleCare anyway, then it's actually ~£85 cheaper overall in the UK.

> In the UK the price includes AppleCare (under EU law), which would cost an extra $249 in the US.

No, it does not include AppleCare. Apple must provide a limited 2 year warranty under EU law. But they still sell their 1-year and 3-year AppleCare plans.