Wages generally rise each year, and with the threshold being frozen this essentially means taxpayers will start having to pay tax sooner than before as their wages grow. 

Ultimately this does however depend on wage inflation until the threshold is unfrozen. 

Once workers’ wages go above the threshold they are taxed at a 20 percent rate for earnings between £12,571 and £50,270.

If their earnings increase even further they will pay 40 percent income tax for earnings between £50,271 and £150,000.