Agree with F30. There isn't a law that says you must be so unwell and many companies release employees in your situation and allow them to start the pension. Yours however isn't operating this and I suspect the trustees have the final say.
Bear in mind that you aren't actually losing anything from this decision - if you WERE able to start your pension now, you wouldn't get as much money weekly if you start it now as if you start it at 60.
Out of interest, is it a money purchase (defined contributions) scheme or a final salary (defined benefits) scheme.
It may actually be advantageous NOT to be getting the pension now. I don't know your circumstances (nor want to know) but one wonders if you have accrued enough NI qualifying years to get your Full Basic State Pension bit (which you don't get until 65 I'm afraid in any event), plus you will surely qualify for some state handouts until age 60 - meanwhile your pension pot might (reasonably) be expected to continue growing for you (global markets performance permitting).