The PM's speech is meant to outline the Government's grand strategy for Brexit. Whilst any clarity is welcome, it will not be the final word by any distance.
The 'divorce bill' figure is meant to reassure the leaders of the other Member States and to build goodwill. They could rightly ask why it has taken around six months for the UK to try to show this type of goodwill?
The Cabinet may be in public agreement but there is no guaranteeing that this will stop the briefings. The PM is a damaged leader, with little authority, and so there is nothing to frighten potential leakers.
The same applies to her party. The Cabinet may like the speech but many hard-line Brexiteers may not be quite so cheery. The same also applies to some newspapers.
There is a real danger that if a figure of €20 billion takes root in minds of the electorate that any final deal involving a higher figure will be seen as a failure or worse a capitulation.
Florence is, apparently, very nice at this time of year. Whether Mrs May will look back on her visit with any fondness remains to be seen.
Theresa May will tell EU leaders there is a shared responsibility to make Brexit work "smoothly" as she attempts to break the deadlock in negotiations. In a major speech in Florence on Friday, she will say history will judge Brexit "not for the differences we faced, but for the vision we showed".