I still expect to be better off there. I rent a 1BR place in Paris for 850 EUR, and I expect to find something comparable in London for 1500 GBP. That means that the flat in London costs about 800 EUR more, which is less than the salary increase I'll be making.
65 k€ = 3358 € per months (on "12 mois") after all taxes, if single living alone.
85 k£ = 4712 £ per month, after all taxes.
Also, 65 k€ is a fairly good end of career in France whereas 85 k£ is a good middle experience in London (and you can get bonus, pension and perks on top).
I live in Harrow in a nice one bedroom for £995. It's in Zone 5 which is far out, but the Metropolitan line has fast trains that go straight to Zone 2 in the morning so you can be in Liverpool Street in around 40 minutes.
That said, if you're thinking of dropping £1500 on a 1 bed you'll have no problem IMO. I was paying £1400 for a 2 bedroom with garden and huge living room in Leytonstone only a few months back. As long as you're not planning on living in Mayfair or Kensington that's a nice budget to work with.
