Some macroeconomic arguments: Is sterling overvalued? (mainlymacro.blogspot.co.uk)
One of the reasons that steel plants have been closing in the UK rather than Germany or France, and that UK manufacturing output has fallen for the last two quarters, is the strength of sterling and the weakness of the Euro. The weakness of the euro relative to the dollar could be explained (at least qualitatively) by interest rate expectations: whenever interest rates do rise in the US, they will surely rise well before they do in the Eurozone. When domestic interest rates are expected to rise relative to overseas rates, a currency should appreciate.
The same logic could be applied to sterling. Indeed some still believe interest rates could rise in the UK before they rise in the US. If the UK looks like the US, you would expect on these grounds for the pound relative to the dollar to be roughly stable, but sterling to follow the dollar in appreciating against the Euro. To a first approximation that is what has happened.