The taxes on international flights out of London are notoriously high and are nearly always passed onto the consumer. However there are ways of getting around them if you start your route elsewhere and connect through London.
While businesses don’t seem to mind this is a lot of money out of the leisure travellers pocket. You can also drop the second leg to Dublin if you don’t check a bag or make sure there is an airport change in the intinery.
A $700 fare difference is considerable when you are sitting in the same seat on the same plane. While a one way from London to Dublin to position yourself would cost between $20 and $70 depending on the details.
The next time you are flying out of Heathrow have a look. $700 would give you a very good night out in Dublin before you fly…..