Tenant law - council landlord

I tried to make a deal for the relinquishment of my council property. My family have been living in the house (first tenants) for over 80 years. We have paid for all repairs that the council should have carried out. I told them I would pay for all current repairs and drop the legal case I was going to take out if they relinquished the property but they won't as they say it is an asset. They will give it up if the property is derelict  but as I told them, it is only in good condition because of the repairs we paid for otherwise it would be derelict. What can I do?