The precise values will vary according to airports, airlines, date and time but to give you a flavour a service from Heathrow to a Spanish airport carries the following "taxes":
UK:
GB- Air Passenger Duty - 5.00
UB - Passenger Service Charge 11.90
Spanish:
QV - Security Tax 1.00
RS - Airport Service Charge 2.80
Airline:
YQ - Fuel/Insurance - 21.00
Actually, on some of the Highlands and Islands routes (not relevant here) the weight of the aircraft was also a factor!