The Scottish National Party is calling on MSPs to register their opposition to the replacement of the Trident nuclear weapons system.
A rowdy and ill-tempered debate has been taking place in the Scottish Parliament over the renewal of Trident nuclear weapons.
The SNP will try to embarrass the first minister in the wake of a BBC survey which suggests the majority of Scottish backbench Labour MPs oppose the move.
The SNP's deputy leader Nicola Sturgeon urged politicians to "speak up for common sense" and vote for a motion rejecting renewal of the deterrent.
Nationalists will use their time at Holyrood to stage a debate on the renewal of Trident.
Labour said the SNP were simply using the Trident issue to make a political point about independence.
The Trident fleet is based at the Faslane naval base on the Clyde.
MSPs will vote later on Thursday on the motion.
Jack McConnell has stated his backing for the UK government's plans.
Earlier this month the first minister said that upgrading Britain's nuclear deterrent with new submarines would allow the country to maintain a nuclear capability and enter possible multilateral disarmament talks.
Opposition debates
The SNP has called on Mr McConnell to take part in the debate and spell out his reasons in full.
However, he has as a matter of principle always declined to take part in opposition debates and has been laid low with bronchitis which means he will be absent from the last First Minister's Questions of the year.
The SNP's motion says that a "full debate" is needed on the replacement of Trident.
The debate will give the Scottish Parliament an opportunity to send Westminster the clear message that Scotland doesn't want Trident Nicola SturgeonSNP Holyrood leader
It urges the UK government not to go ahead with the proposals contained in the white paper which was published earlier this month.
Prime Minister Tony Blair outlined plans to spend up to £20bn on a new generation of submarines for Trident missiles.
The SNP's Holyrood leader Nicola Sturgeon said: "I oppose the replacement of Trident and will be proud to lead the SNP's case for nuclear disarmament during the parliamentary debate.
"The debate will give the Scottish Parliament an opportunity to send Westminster the clear message that Scotland doesn't want Trident.
Key questions
"Many MSPs, in all parties, oppose Trident and I hope that they will all vote with their consciences on Thursday."
Labour MSP Jackie Baillie, who has the Faslane base in her Dumbarton constituency, dismissed the SNP's arguments.
She said: "It is their lack of honesty about jobs, they have not thought this through. On the one hand they argue for the refitting of submarines in Rosyth and they don't actually believe in Trident at all.
"There is a dishonesty there which will devastate my local community in terms of its local economy. If you are mature and sensible in your politics you need answers to those key questions and they don't have any."
'Socially useful'
Communities Minister Malcolm Chisholm has gone public with his opposition to Trident, as have six Labour backbenchers at Holyrood.
A BBC survey earlier this month found that a majority of backbench Scottish Labour MPs disagreed with the plans.
30 of the 59 MPs said they were either "definitely" or "probably" against the Prime Minister's proposals.
The Greens will also argue against the replacement of Trident during the debate.
They say the weapons system should be scrapped, with the workers at Faslane and Coulport redeployed in "socially useful work".
