I retired last year at 60. I am recieving state pension. I would like to do intermittent work , holiday cover etc in a self employed catagory. Will I have to pay national insurance?
Trouble is, holiday cover and the like is very unlikely to be acceptd by the Revenue as self-employment. If you're doing the job of an employee while he/she is away, you'll have the same employment status as they did. You're not going to be in business on your own account. See this link: http://www.hmrc.gov.uk/employment-status/index .htm#2
The employer does, rather. Point being that it's just as expensive to the employer to take on somebody over pension age as it is to use a pre-pensioner (if that's a word).
You are right, but that is not what was asked in the question. In the sort of work viz48 intends to do then I doubt whether his/her earnings will even reach the level where NI contributions are payable.