What are National Insurance and income tax and what could change in the Budget?

In anticipation of the November Budget, there is speculation about possible changes to income tax and National Insurance (NI) by Chancellor Rachel Reeves, potentially impacting working people's taxes. Proposed adjustments could involve freezing income thresholds to raise tax payments. National Insurance contributions support benefits and the NHS, with rates varying based on age, employment status, and income. Employers and employees pay NI, while income tax is levied on earnings exceeding a tax-free allowance, with different rates for various income brackets.