Tony Blair has told MPs no decisions have been made on replacing the UK's Trident nuclear arsenal.
The issue of Trident was controversial from the outset
Quizzed about the issue at Prime Minister's Questions, Mr Blair said the government remained committed to having an independent nuclear deterrent.
But he pledged ministers would listen to the views of MPs on the issue.
The Trident fleet of submarines is not due to be decommissioned for about 20 years when it will either need to be replaced or upgraded.
Critics say it is outdated, designed to deal with the threat posed by the Soviet Union during the Cold War, and should now be disbanded.
Mr Blair told Labour MP and ex-minister Chris Mullin that it was too early to rule in or rule out any particular option.
"As we set out in our manifesto, we're committed to retaining the UK's independent nuclear deterrent but I'm sure there will be plenty of opportunities to discuss this before the final decision is taken."