Former Tory minister Crispin Blunt will vote against renewing Trident because it fails a cost effectiveness test, he said.
Blunt, chair of the foreign affairs committee, believes he will be the only Tory MP to argue against the Government's pro-Trident position.
The cost of Trident comes at the expense of the rest of the defence programme and the Government should balance its defence spending, he warned.
He estimates it would cost up to £179 billion in total to renew and run Trident for the next 32 years.
He said during the Commons debate: "This is a colossal investment in a weapons system that will become increasingly vulnerable...
"I believe we will have to throw good money in order to secure it, tens of billions of it more than already estimated, to try and keep it safe in the years to come."
The nuclear deterrent is of less relevance in today's world and surplus to the needs of Nato, while advances in technology could also results in submarines being easily traced in the future, he added.
The former justice minister also warned it could be "instrumental" in the undoing of the United Kingdom by sparking stronger nationalist feeling in Scotland.
He said: "Britain's independent possession of nuclear weapons has turned into a political touchstone for commitment to national defence, but this is an illusion.
"The truth is this is a political weapon aimed rather effectively at the Labour Party."