You will have to pay tax if your combined earnings and pension are above the threshold, so if your pension was £10000pa & you earn £10000pa then your total income is £20000, that, less the allowance (I think it's around £10000 for a person in receipt of state pension) will be your taxable income. The only snag is that they can't/don't take tax from the state pension at source so they take it all from your other income :-( You really could do with professional advice, deferring the state pension means you get more per week when you do take it but it can depend on how healthy you are as to whether the risk outweighs the benefits etc etc.