According to figures quoted by The Guardian, London faces a possible £5bn funding hole due to CrossRail overruns which will directly impact the expansion and renewal of the Tube:
The alleged funding gap covers improvements to London's tube network up to 2017. Transport for London is currently budgeting the works programme for the period and senior figures believe it could be up to £5bn short. One source said Livingstone had underestimated the financial support needed for the Underground network when he negotiated the Crossrail deal last year.
Such a figure would be disastrous for London, especially in the run up to the Olympics in 2012. Either CrossRail will suffer through funding being diverted to fund essential projects before 2012, or the Mayor will have to go cap in hand to an unsympathetic Government.
It is still unknown how the Labour Government will react to such a move from a high-profile Conservative Mayor.
The only other solution for Mayor Johnson is to raise funds through increased journey fares - certainly an unpopular move with Londoners who will likely have a short memory when he faces re-election.
This possibility comes on the back of news in The Independent that the simplification of train fares is being used by operating companies as an excuse to raise fares:
The new system, partially introduced yesterday, was supposed to make buying tickets easier by reducing the number of reservation types available to just three. But passenger groups warned that a number of train companies had already used the changes to scrap some of their cheapest fares by cutting the number of off-peak services and said more may follow suit when wider changes take effect later this year.
Neither will be popular moves for the Mayor, especially as he will be linked by association to his predecessors' misleading policy of keeping fare rises below the rate of inflation.
Against this backdrop, it is heartening to know that Mr Johnson has appointed Steven Norris to sit on the boards of both TfL and the LDA. His role, one of co-ordination between the agencies, should see efficiency drives which, whilst they won't offset the potential fare rises on the horizon, should save money for the Mayor to re-invest in the network. Despite this news however, it is clear that there are to be troubled times ahead.