Can I work while waiting for my new visa decision?

I was on a Tier 4 student visa from the US.

I have finished my course and my visa expired on the 5th of February but I have an FLR(M) application in with the Home Office since the 2nd of February.

What are the rules on working while my FLR(M) visa is being processed? I have read endlessly that you retain the working rights you had whilst on your previous visa while you wait for the decision on your application. However, yesterday a NI employee told me this was not the case.

Does any one have any insight on this?