The earnings rule is used to reduce only your basic pension. There is no reduction of your graduated pension or the additional pension related to your earnings after 9 April 2012.
But any extra you earned on your basic pension by working past pension age can be reduced or lost completely if your earnings are high enough. The reduction of your basic pension by the earnings rule is quite separate from tax.
There is no reduction of a widow's pension whatever her earnings, though if she is over sixty and claiming a retirement pension she may lose a small amount of that. A widow who has remarried and earns over £199 a week may lose some of her retirement pension paid on her late husband's contributions.
If you work after reaching pension age, you should not pay any National Insurance contributions. Your liability to pay contributions stops on the last payday before you reach that age. You should ask your employer to check that you are not paying contributions.
Some married women still retain the right to pay a lower rate of contribution, 6.69 % of their earnings. If you still work, you should ask the local DWP office for advice as to whether it would be worth your while to revoke your right.
Ask them if you would have any right to a pension of your own at the age of sixty or could obtain a pension by paying some back contributions. Make sure that you get their advice in writing in case it turns out they advise you wrongly. If you want to revoke your right to pay lower contributions, obtain leaflet NI.1 from your local DWP office and fill in the form, CF.9, at the back of it.
Many people who retire . . . ... see: Working in retirement - Married Women