The spending review that Chancellor Rachel Reeves will deliver this week isn't just a big deal in Westminster, it will also prepare the ground for next year's Senedd election.
She will tell UK government departments how much they will get to spend over the next three years.
In doing so, she will also reveal the funding available to the Welsh government that voters will elect next May.
Various parts of the UK government have been negotiating with the Treasury.
The Welsh government – which is responsible for the NHS, education and other big public services – has been doing something similar.
It can raise money through taxes, but the vast majority of its budget comes in a grant from Westminster.
That means the chancellor's decisions have a huge influence on what the Welsh government can and cannot do.
In Cardiff Bay, they await her statement with bated breath.
