I am not talking about Thameslink here, or even Crossrail. No, this scheme involves an even more radical mode of transport - and rather fewer wheels per vehicle.
I am talking, of course, about Boris' bike hire scheme. Even now, final decisions are being made about the appointment of its private sector operator. An important decision, since the operator will define the type of bike, the payment system, safety and security provisions, and the repair and maintenance regime.
Unlike the other 30 or so cities around the world where similar schemes have been implemented, most notably Paris and Barcelona, London will be funded mainly by the public purse. Although Transport for London is looking for a main sponsor, the scheme will be driven and promoted mainly by the mayor.
The comms challenges for him, his authority and the scheme's private sector operator will be immense, certainly as much as they were for congestion charging.
The political stakes are equally big. All the key project milestones will happen in the run-up to both the next general election and the next borough elections in London, and with the 'go live' scheme shortly afterwards.
There have already been PR issues over helmet wearing (unenforceable) and cyclists using their own locks (selfish). By the time those 6,000 bikes are finally launched in May 2010, they will be carrying major political reputations, as well as nervous tourists, onto London's busy streets.
And as Boris discovered to his alarm last week, cycling in London can bring you closer than you might like to an HGV with a loose back door.
So from one cyclist to another, I would just like to say: Boris, be careful. Putting your faith on two wheels is a dangerous business.
- Luke Blair is a director at the London Communications Agency.