The chances of you getting a realistic figure are remote. Not because of all the different bits and pieces in terms of payments for this or that but because most people can't separate idea's from reality. And the system of payments, shifts and hours are deliberately confusing. There is HM taxes before the salary gets to you and only after that happens can one begin to see reality poking his little head out.
Reality is what gets put in the bank account at the end of each month
A realistic ballpark figure for someone certifying at LHR for the worlds worst airline gets approximately 2700 GBP into his bank account.
A guy from another outfit not so big will get about 3000 GBP in his account at the end of the month.
From that he must then pay mortgage/rent/council tax/20% VAT on everything/road tax/car tax/petrol tax/sin tax/various registrations and so the list goes on...and on hahaha.
