Each individual is entitled to his or her allowance (PA) of £12,500 for 2020/21. The PA reduces an individual’s taxable income. For those with a gain of over £100,000, the allowance is restricted.
After deducting income from PA, a series of band rates are pre-allocated to your savings (this can include income from salary, self-employment, revenue, and pension), and then to your savings, and finally to any share of income.