The shifting arguments for London's New Bus
The New Bus for London is undoubtedly a striking addition to the streets of London.
What's also striking for those who have followed its story is how the argument for it has shifted.
The New Bus was born in the 2008 election campaign and it helped propel the now Mayor Boris Johnson into City Hall.
Who actually came up with the idea isn't clear but soon we'll have hundreds of the new buses on the street.Anti bendy-bus
Initially the New Bus was linked to the anti-bendy bus argument, that Mr Johnson was making at the time.
This did have resonance with people who didn't like the bendy buses - although their road safety record was much better than was portrayed.
And the New Bus seemed to appeal to nostalgia and strands of libertarianism with its hop-on, hop-off platform and in my experience the reaction from the public is usually positive.
The idea of a bendy bus killer seemed to hit a nerve. Mr Johnson then deposed the Labour Mayor Ken Livingstone.
Looking at my notes from the time, the cost to build the new bus was then quoted as £100m.
Then the argument changed.
At the launch of a competition to design it, I specifically remember it becoming about providing a green, clean bus to try and solve the air pollution crisis in London.£200m bill
As the project developed the costs also began to shift and change. The prototypes and the research and development cost £11m for eight buses.
When they were deemed a success a further order for 600 buses was meant to be paid for by the bus operators.
That didn't happen and Transport for London (TfL) is now footing the more than £200m bill for the 600 buses - it says it will save money in the long-term. It will also pay the £11m development costs.
And the cost of the actual individual buses has also shifted. Remember this is one of the flagship projects of the mayor.Running costs
In his 2012 transport manifesto the Mr Johnson said the New Bus would cost "not cost more … than an existing hybrid". That is usually about £300,000.
The new buses will cost £354k each. Here's a recent TV piece I did on it.
Today in the Telegraph the mayor says: "If the new bus fulfils the promise it has shown in tests, we will be able to save so much on fuel that it will actually come out cheaper then our current hybrid buses."
So Mr Johnson is now including the savings in running costs, to say the new bus is cheaper than an off-the-shelf hybrid.
Also the argument for having the buses has shifted again.Considerable pride
Now they are a reason to invest in London's transport as it provides jobs and growth across the UK. The mayor is using them to try to persuade the government not to cut TfL's budget.
Perhaps City Hall will say all its arguments for the New Bus are valid. Perhaps they will say all the costs are justifiable and big changes are inevitable in such a project.
There is also considerable pride at TfL and City Hall that they have delivered such a bus.
But you have to remember this isn't a normal transport project - its roots are deeply political and as such it's a chameleon - and can and will be used to influence the political landscape.