My father passed away and I have been living with him in council accommodation for over a year, I am on the council tax, electoral role, gas and electric, phone and my benefit is paid to my dads address. I have been given a notice to quit and told I have to get out and they are not responsible to rehouse me. What can we do??

Find new lodgings. The housing was in your father's name and is probably not inherited.

You can consult a solicitor to try and appeal the council ruling, but they probably have the law on their side.

I have a letter that says I am an authorised occupant

But I'll bet that is valid ONLY while your father was alive. Once he passed, the authorization ended. I am pretty sure that's what the council will say.