Hi,
Congratulations on the impending arrival of the sprog!
Thanks phatbeetle for the little recommendation there!
Some good points as per usual from the UKY establishment already !
My background is similarly from an IT background and specifically, within finance, tax and business infrastructure. Whilst £64K is a very good salary, as already indicated that you'd be in the top 5% in terms of salaries, I'd also put forward it's not a 'great' salary for living and working in London. You will of course be 'comfortable' within the overall view of things, and seeing as you are coming in from Tokyo/Japan which also has similarly high 'expenses' for day to day living etc you'll already be used to high costs and perhaps some 'compromises' in various elements within your life/lives.
A £64,000 salary breaks down to £43,901 take home after tax and national insurance (source -
http://www.thesalarycalculator.co.uk/salary.php)You'd be in the 'higher tax bracket' of 40% and National insurance I think will be around 11%, so in total, you'll be 'taxed' around 51% of your income. If you have pension contributions etc then take off the associated amount as well.
This comes to around £3658 per month take home. Assuming a modest 2 bedroom flat in st Johns wood at perhaps £575 per week is £2300 in rent. Utilities, gas/water/electricity £100/month (estimate) Council tax £150/month (estimate) food at £200 per month, travel work/pleasure - 300/month (esitmate), Mobile phones X2 £50/month, contents insurance £35/month (estimate) Clothes/personal items £50/month etc etc.
That's going to take up perhaps around £3100 or so, leaving you £500 leftover for the month or £125 each week. £125 can be spent in a snap on a couple nights out each week at a nice restaurant! and in my quick figures above, I've not included things like telephone line rental, TV Licence, Cable/Satellite TV subscription, I'll assume you won't have a car, savings etc, so the potential for you to spend all your income on basics and some luxuries is all too easy to do! and once the little one arrives... plenty to spend there!
I know you can perhaps save by going to a lesser priced apartment etc, but overall, you'll not have 'much' left over by the sounds of it.
Only you know your exact requirements as a couple and soon to be family, and where or what you spend your money on. In a nutshell, as mentioned in posts already, you'll be comfortable but not really to the extent of having a good surplus left over each month. Career wise, I'd see if you can speak to your employer about potentially returning back to Tokyo after a few years or perhaps onto another branch/country etc in which the company operates etc.
Good luck !
Cheers, DtM! West London & Slough UK!