Agreed, and even many experienced developer jobs are advertised at only about £40k. When you look at the cost of living in London, its simply not worth it. I'm amazed they manage to recruit at all frankly. You could quite possibly have a better material lifestyle by living in a cheaper area in northern england and stacking shelves in a supermarket for a living. I can never understand why so many high tech companies base themselves in London, when they could relocate up north and get very talented developers for much less who will stick around and who will be happy too as a £20k salary in the north actually gives them a chance of buying a house.
London isn't a half bad city to live in. Good luck enjoy the kind of communities we have here (literally hundreds show up for the HN meetups) while stacking shelves in a supermarket up north.