The top 50% and especially the top 10% of the country are currently under taxed, there definitely is room to tax more if its targeted at the right people.
Is it your preference to not have a social tariff?
A social tariff would solve a lot of issues for the government, it provides a solution that lasts until the policy is dropped, so they wont be under as much pressure to keep issuing new cost of living payments. But it also will create issues, as there will be a line drawn on who gets it, and those who fall just outside that line will feel hard done by. Given how harsh the new WHD is, it wouldnt surprise me if they use the WHD criteria for a social tariff which will leave a lot of poor people not getting on the social tariff. I dont think they will give it to the full 8 million that got the cost of living payments, as that would require a lot of subsidy.
I have no idea how far down the income bands tax would have to increase and by how much.
I feel it would be quite far.
Even us in an average house with above average income would probably shoulder the burden.
However I'd have issue with if it started really penalising you for good practice with money.
For example if it was(probably impossible) to look at disposable income we'd be hit hard. Might as well take on an increased mortgage etc to reduce it.
But overall I don't think there are enough ordinary people left to tax to plug the gap. By that I mean there are so many people needing help and not enough above to balance it out