Occupational pension schemes are set up by employers to provide pensions and life assurance benefits for employees, for example, a tax-free lump sum payable if they die before retirement to their widow/widower or other dependant's).
Occupational pension schemes are either:
Contributory,
where you give part of your earnings
(typically 5% of your gross salary)
in addition to your employer's
contribution.
OR
Non Contributory, where your
employer makes all the payments.
In either case your employer has to pay for a substantial part of the administrative costs of the pension scheme, by law. And you also get tax benefits from the Inland Revenue.
If you can join an occupational pension scheme then do so. Refusing it is likened to turning down a pay rise. You may dislike your pension payment / contribution being held back from your monthly pay check and going into your occupational pension scheme. But it's being saved for you and will remain your money.
Use one of our free Pensions Calculators to find out what your occupational pension is worth.