The pension that Sir Robert will be entitled to is a "final salary" employer's scheme. Presumably he earns about £160k pa and is entitled to a lump sum of one and a half times that sum and a pension of half that sum. All standard stuff with the amounts being related to his final salary and his lifetime salary determining the contributions he has made.
By contrast the State Pension scheme is not a pension scheme at all. It is a flat-rate payment made almost regardless of contributions. Leaving aside the requirement to have made NI contributions for a minimum number of years, a person who has earned (say) ten times the average salary throughout his life gets the same "pension" payment as somebody who has earned only just enough to make NI payments. There is no real link between contributions made and payments received. Further than that, somebody who has made no contributions whatsoever will receive more in payments made after retirement age than somebody who has worked for most of their life but failed to achieve the minimum number of NI contributing years. This is because they will be guaranteed a minimum payment which is at least equivalent to (and, depending on their circumstances, often higher than) the basic State Pension. They may well receive more than Sir Robert and his State Pension will form part of his taxable income and will therefore be subject to income tax, whereas the person dependent solely on the State payments will have no deductions made.
It is important to understand the difference between these two things.