This is the date for upper tier authorities (ie unitaries and county councils) to express an interest in joining the government's priority list to become a Strategic Combined Authority. The outlines are set out in the 16 Dec 2024 white paper on English Devolution. It's been sold as 'Taking Back Control' (from Whitehall) but I think we've heard that one before, and informed opinion regards it as 'decentralisation', not 'devolution'.
For the people of Sussex this may result in a Mayoral Strategic Combined Authority on top of 3 unitary councils - East Sussex, Brighton & Hove + extra bits, and West Sussex, with no more district councils. Whilst some combination of the above just might be an improvement, especially if it led to a significant increase in funding for the area (but I'm not holding my breath), if accepted for the priority list, it's likely that this year's West Sussex County Council elections will be cancelled!
This would result in the details of any new local government organisations being negotiated by the existing county councillors. If, like me, you are not happy with this prospect, then please write by 9th January to Jim McMahon, the Minister of State for Local Government and English Devolution, using this handy template (from Horsham Green Party) and demand local accountability!