As Mr Cameron and his aides carried out marathon talks in Brussels, the North Shropshire MP carried out a round of critical interviews.
The former environment minister is emerging as a key figure in the Brexit camp as a referendum looms on whether the UK should pull out of the EU.
Mr Paterson said the talks had been "very, very disappointing" so far and had "come nowhere near" what was best for the UK.
He said: "The Prime Minister's asking for changes to the benefits regime, none of which is permanent, it can be reversed by the European Parliament or reversed by the European Court of Justice if we don't get treaty change.
"What we were looking for was real fundamental renegotiation as the Eurozone moves towards effectively a new country.
"That's the real negotiation behind the scenes, and that will leave the UK outside. We'll never join the Euro, we'll have some sort of associate status which is not yet clear – but I'm absolutely clear that we should leave the political and judicial arrangements of the EU.
"We should establish a trading relationship and co-operation across a whole range of activities, science, academia, security, arts, whatever, but we make our own laws in our own parliament."
There was more discontent from Mr Paterson's Tory colleagues in Shropshire, who among other issues said there should be more discussion on a better deal for farmers.
Daniel Kawczynski, MP for Shrewsbury, said the "intransigence" of other European countries was frustrating and that there should be more discussion on the Common Agricultural Policy. "If you look at the chaos in the Eurozone you would have thought they would be more amenable," he said. "The way these negotiations are going it is pushing me towards pulling out of the EU. The UK will thrive either inside or outside.
"If we pull out I think our economy is so resilient we will be able to sign a trade agreement with the EU."
He said with the UK buying more goods from the continent than it exported, EU countries would be "desperate" to strike up a trade deal with the UK on its exit. He said talk of the UK being a member of the EU for security reasons was also a red herring.
"We have kept peace and security through NATO, not the EU," he said. "To me the issue is all about sovereignty and who governs Britain.
"No powers in the current negotiations are being transferred back to the UK and the main subject seems to be benefits for migrants. I'm very disappointed that there has been almost no discourse about CAP reform. It's extremely important we get the best for Shropshire farmers."
Mr Cameron had one supporter in Mark Pritchard, MP for the Wrekin, who said the talks marked a "historic" moment for the Conservative Government.
Mr Pritchard said: "The Prime Minister is clearly battling very hard for the British interest. I am sure he will make even more progress over the coming hours. This is a historic moment."
Ludlow MP Philip Dunne and Lucy Allan, MP for Telford, were unavailable for comment.