Rail franchise bids across London and the commuter belt are on hold after the government admitted it got its sums wrong on the West Coast Mainline.
Decisions on who will run services out of the capital to Watford, Reading, Southend and Brighton will be delayed while the franchise process is examined.
Mayor of London Boris Johnson says this strengthens his bid to bring commuter services under his remit.
Boris Johnson says the rail franchise fiasco strengthens his case for taking charge of London's commuter services.
The future of rail services in the south-east has been thrown into disarray after ministers called a halt to several franchise competitions.