As mentioned by the ONS and picked up by the FT Alphaville team, London house prices are up 9.7 per cent over the 12 months to July.
With the average London house costing £438,000, the capital gain was worth £38,729. The average London household post-tax wage, however was of £38,688 in 2011 (apparently the last year for which the ONS has statistics).
Now, there are some issues with cross comparison and the FT freely admits that it hasn't factored
capital gains, paying foxtons, getting the money while having somewhere to live, potential transaction costs but as the article concludes;
"London houses don’t sleep or take holidays, and earned £4.42 every single hour of the year to July."