Lower and middle income workers people can't afford to pay any more tax. They're already paying ridiculously high housing costs, childcare costs, council tax, utilities, student loan repayments, NIC, etc. We can't keep squeezing the same people.
The main category of people who need to pay more tax are those with non-working income, i.e. interest, pensions, property rental income, etc. who are paying way too little.
We really can't justify a pensioner with total income of £50k from a mix of pensions, property let, interest and dividends paying less than a worker on £50k.
We need to "make work pay" to get more people working and more part timers working more hours. Hiking taxes on workers will do the opposite.