Zero earned income. You get about £60-200 from the state per week so lets call this a £60 basic income. Typical unemployed.
Annual income £12K. No tax and no subsidies. We could rebrand as £60/wk basic income = 3K/yr and and 25% tax on the 12K. Typical minimum wage earner.
Income £50k. Roughly £35K in your pocket, £15K tax. Rebrand as 18K tax less 3K minimum income.
The system kind of works. One of the main problems is that there is a very steep effective marginal between zero income and minimum wage - a lot of people end up about equally well off in the short term whether they do nothing or flip burgers. This would be better under a straight basic income system.
I think you could improve the basic income set up by something like karma points where you get a bit more money if you are productive even if it's doing something unpaid like charity work or writing poems and less if you are criminal etc.