Councils asked by the Government to volunteer to run congestion charge experiments would have been failing in their duty had they not thought long and hard about the financial inducements thrown in their direction in return for pushing forward with politically high-risk ventures.
Just how much money - how many improvements to the bus, tram and train network - might be secured in return for taxing motorists to drive in and out of cities during busy periods has been a matter of intense speculation.
But few local authority leaders can have been prepared for the extraordinary scale of the Whitehall largesse, as amplified today by Transport Minister Rosie Winterton who is expected to announce what amounts to a bribe of unprecedented proportions.
Eight of the 10 Greater Manchester councils are ex-pected to pocket riches beyond their wildest dreams for agreeing to run the first major road pricing scheme outside of the capital. A £5 levy will be imposed on vehicles travelling in and out of Manchester at peak times, but the reward for the local authorities amounts to £3 billion for improved public transport and infrastructure.
Birmingham and the six other West Midlands metropolitan councils were originally competing with Manchester to pick up the congestion charging mantle, but decided to pull out of the race when it became clear political agreement could not be reached.
There were also severe doubts from business leaders who remained to be convinced that the net impact of charging people to drive into urban areas, when other English regions impose no such charges, would be anything other than bad for the regional economy and potentially disastrous for the competitiveness of West Midlands' industry.
It was a tough call to make, since the £3 billion on offer would have more than paid for extensions to the Midland Metro tram network along with much-needed improvement to bus and rail services.
The amount would have enabled the councils and the passenger transport authority Centro to deliver a wish-list of infrastructure projects far more quickly than anyone could have dreamed of.
But the councils were right to suspect that voters would not take kindly to the grubby way ministers set about inducing local authorities to carry out the Government's dirty work.
The political backlash in Manchester is only just beginning, but Labour MPs must be wondering about the wisdom of imposing yet another tax when the cost of motoring is rising almost on a daily basis.