In many respects the UK pays the most duty in Europe now - fuel, booze and cigs being the prime examples. A single country will mean one rate for all. VAT, income tax and excise duties will be the same for all. So, our region loses out in direct taxation but gains, in some cases massively, in indirect taxation. The EU constitution that Tony is so keen on, and won't let us vote on, will make it happen.
The UK, even though Blair has raixed taxes massively since 1997, is still the lowest taxed country in the EU, and this could only change or else fiscal problems would occur around other EU states. Ergo, our tax rates would go up to meet the mean average, or more likely the highest. Vehicle tax and excise would shoot up. You are assuming the best from what the EU constitution will bring.
In a best case scenario EU officials, not elected representatives, and that is in the EU constitution, will make laws that have primacy over State laws made in individual countries, they will also make diktats and decisions that have primacy over UK laws and decisions. At best we will be a province with our own provincial and federal laws and taxes.
The UK economy is very different from mainland European economies, and therefore there are different strictures and fiscal rules that we must follow.
A single tax regime may suit Germany and France, but not the UK, and vice versa, but never, in a million years, will the taxes come down to meet ours, and there is no way the Government will forego the taxes gathered by duty and vat and excise as it is today, ergo, taxes will rise, inevitably.
The Germans and French especially are depserate to get the UK into full EU membership because their problems with the pensioners is much worse than ours and they need our money and strength in economics around the world in order to service their massive shortfalls.
The bottom line is that they need us more than we need them because over the past two decades the UK has become a global economy while the EU states have staganted in their own little club. Why tie ourselves to decaying European economic ideaology when we are glaobal and prospering without them? Don't forget it costs us £6 billion a year more than we put in to the EU. I say save the money and let them rot.