The breakeven math that DWP does not put on the leaflet
One year deferred means you go without £12,548 from age 66 to 67. You start receiving £13,276 from 67 onwards — £728 more than if you had claimed at 66.
It takes until age 83.2 to recoup the £12,548 you left on the table. Only then does the deferral start paying out net-new money. Live to 85 and your lifetime profit is about £1,300 — that is £68 a year for the gamble of dying before breakeven.
Defer for three years and the numbers get worse, not better. You forgo £37,644, and even with the higher boosted payment of £14,727 a year, breakeven pushes past 84. The longer you defer, the older you need to live to justify it.
Put another way: deferring from 66 to 70 — a four-year wait — means you go without £50,192 in total. Your boosted pension from 70 would be £15,454 a year, compared to £12,548. The annual gain is £2,906. Divide £50,192 by £2,906 and you get 17.3 years — breakeven at 87. The average British male dies at 83.7. You would need to outlive the average by nearly four years just to get your own money back. That is not a retirement strategy. That is hoping to beat the actuarial table that was designed by the people selling you the deal.