Hunch. ONS figures from 21 October put rent growth in England at 3.99% before rounding, so rents there must rise at least 0.36% in October alone for the figure to stay at 4.0%.
The England market resolves on the same ONS release: YES if it prints rent growth in England in the year to October 2026 of 4.0% or higher, and NO if it prints 3.9% or lower. Changes to the September figure do not count, and the date rule and backups are the same as for the 3.8% market.
We looked for cases where ONS published a monthly figure for UK rent growth in the first six months of a law that made it easier for tenants to challenge a rent rise, in the largest part of the country only. The ONS figures start in January 2016. We found five such months, May to September 2026, all after England's new law, and checked whether yearly growth fell below the month before.