The average house price in London is due to hit 400,000 in 5 year's time, according to what I saw on the news last night. In places like Camden, you currently pay more than half a million on average.
They say to buy a house that could function as a family home (i.e. not a tiny 2bedroom flat) in London you need a salary of around 55,000 - teachers and nurses earn half that.
It's something I am thinking about too, but not sure about doing it in partnership, buy-to-let would be preferable, with 1-2 boarders. But then I pay only £380 a month for a great room at the moment in a good location so to go from that to a £1600 a month mortgage in a small 2-3 bedroom apartment seems a bit out of kilter with my circumstances.