Could integrating the suburban London railways dramatically improve services and cut costs?

Boris Johnson suggests that it will, and that he is the man to manage it.

London Overground is already one of the best-performing routes in the country, with reduced levels of crime and high standards of reliability, while London Underground is enjoying massive investment.

Of course there is always room for improvement and greater efficiencies could free up extra funding to invest in the railways, in order to keep up with predicted demand and future pressures.