Indeed…and outside an ISA savings interest income on much over £250k would mean you should probably do a tax return anyway as the interest is likely to exceed then annual allowance. It was much simpler when all interest income had tax deducted at source unless you applied for it to be paid gross, which then put you on HMRCs radar. Though I assume they still get the info from banks anyway?
Technically not everyone has a PAYÉ identity against which a tax code can be applied, which is why savings interest requires a tax return. But everyone should have UTR, tied to their NI number. If there are people (I am sure there are) that have income that they don’t declare to HMRC then they can’t expect to get the benefits of the welfare state IMO!!
Nevertheless, at the level set for withdrawal of the WFA, a million more people will be pushed into fuel poverty so a little more thought as to the impact and mitigating it would have been good. Charities in the sector are flat out at the moment dealing with worried pensioners.