What explains the euro's remorseless rise against the GBP?

I should have thought the euro-zone was in deep trouble. There was the Greek bailout, which seems likely to fail, now there's the Portuguese rescue package. Previously Ireland was in catastrophic difficulties. Spain is far from secure. Against this, the British economy isn't performing brilliantly but it's not in anything like the kind of crisis which overtook Greece and the rest and which is costing the European central bank and the German economy a cascade of money. What sense does the relative strength of the euro make ?