I don't think Home office cares if your passport is expired or not. If you don't renew it you might not be able to travel and that is the only thing that will be a problem for you. You will just have to get British Citizenship and then apply for British Passport. Just remember to write statement at the time of citizenship application that you never got another passport because your home country refuse to give it to you.  Because Home Office might question you or you may want to call them and find out what is their policy. As far as I know all they are interested in is the date you got Visa, Indefinite stay and if you were out of the country for more then time allowed. Passport is the only document that can give you this information and satisfy Home office.

I am just curious what is your country that is taking basic rights from you of renewing passport. I am sure there is a way of getting a new passport somehow. Did they give you any reason fro not renewing your passport?

It is the Zimbabwean Government. Actually, it was just before the passport was due to expire that they refused to renew it as I had lost my Zimbabwe Identification Card, and they said that without it I could not renew my Zimbabwe passport (even though I have my original birth certificate and the identification number is in the passport). I would have to travel back to Zimbabwe to replace the ID before I could get the passport renewed. Needless to say, I didn't go back to Zimbabwe, so the passport has expired and I have just left the matter at that. Maybe in the meantime I should write to my Goverment explaining the situation again and get a letter back from them to attach to my Citizen Application with their refusal / acceptance to renew the passport. What do you think?

I would gather as much information as possible. Burden of proof is on your shoulder but then again Home Office might not require the passport because main reason of becoming British National is to get a British Passport.  Anyway, it can only benefit you if you have a letter from your embassy.  There is no harm in trying and you will be able to tell home office that you tried.  That's just my thinking.

Always prepare for the unexpected hey? I will do just that. Thanks for the help and advice.

My passport that holds my ILR has expired and the country I come from absolutely refuse to renew it. Do you think this will hinder my Naturalisation as a Citizen application at all?