Alex Salmond, the SNP leader, accepted the invitation, but Jack McConnell, the First Minister, did not.
In the end, the debate took place between Nicola Sturgeon, the SNP's deputy leader, and Wendy Alexander, the former enterprise minister, after Mr Salmond also withdrew, insulted that Labour had not even managed to get an Executive minister to take part.
This was not an isolated case. Last night's debate was one of a number of opportunities to debate with Mr Salmond that Mr McConnell has turned down in the past few weeks.
He declined to appear with the SNP leader on Channel 4 News on 10 January, he refused to appear with Mr Salmond on the Today Programme on 16 January and on the Newsnight Union special the same evening. Then there was last week's BBC Question Time programme, featuring all the main Scottish party leaders - except Mr McConnell, who sent Lord Foulkes of Cumnock, a former Scottish Office minister, to debate with Mr Salmond.
Mr McConnell insisted yesterday he had a very good reason to turn down last night's Chamber of Commerce debate.
He said: "I have a long-standing engagement with nine or ten Cambridge University professors and leading figures in the UK life-sciences industry, one of the fastest growing commercial sectors in Scotland.
"That event is the kind of thing I do as Scotland's First Minister and that's why I believe I have to do my job until the end of March."
This appears to be a sound argument. Unfortunately, it does not quite tell the whole story.
The Chamber of Commerce organisers offered to stage the debate on a day to suit the First Minister's diary, but he still declined to take part. This is not just a clash of diary dates or the result of a busy schedule: Mr McConnell has decided to remain aloof from all leaders' debates until the election campaign for real starts next month.
There are some solid reasons for this: it is always easier for the opposition to score points than it is for a member of the government. Mr McConnell wants to appear statesmanlike and he does not want to get sucked into debates with his deputy, the Lib Dem leader, Nicol Stephen, while they are still working in government together.
However, this week's Scotsman-ICM poll, which gave the Nationalists a five per cent constituency and four per cent regional lead over Labour, has led to unease within Labour ranks at Mr McConnell's tactics.
One Labour source said: "It is a difficult one. I know why he is not debating with Salmond but we are starting to get beaten on this. The jibes about 'running scared' are starting to get through."
And another insider added: "Jack will come out fighting, there is no doubt about that. But I will concede that there is a vacuum at the moment and Alex is exploiting that perfectly."
But there is something more important than just leaders' debates at stake here. The issue of Mr McConnell's refusal to take part in head-to-head debates with Mr Salmond is symptomatic of problems within the whole Labour campaign.
Labour is not succeeding in setting the agenda and the party's strategists are being out-thought by their Nationalist opponents.
What is needed is responsive and flexible leadership: from Scotland, not from Westminster. However, the message from party managers in London yesterday was clear - the direction of the campaign will not change, indeed it will get even more negative and aggressive as the election draws near.
A senior Labour source said Mr Blair had demanded Labour keep up "relentless attacks" on independence. The Prime Minister has also flatly rejected any suggestions that Labour should put more emphasis on "non-constitutional" issues.
"This is a battle for the future of the UK, and people have to realise that," said the source.
This goes straight to the core of Labour's problem. The agenda is being set by party leaders in London who see everything in black and white - viewing everything through the prism of independence.
In Scotland, the situation has much more nuance.
If Labour is to prove it deserves to govern for a third term, then the man who seeks to lead that government has to lead that debate.
When one senior Labour insider was asked why Mr McConnell had ducked so many debates with Mr Salmond, he replied: "He's running the country, and I'm sure that's a very big job."
The issue for Mr McConnell is whether he will have a job to go back to if he fails to take control of Labour's campaign soon.
A TALE OF TWO FIRST MINISTERS
LABOUR'S problems with leadership and direction in Scotland do not seem to be replicated in Wales.
Rhodri Morgan, below, the First Minister of Wales, was relaxed enough about the impending election to be in New York yesterday, St David's Day.
However, when he is at home, he has shown no reluctance to debate with his political opponents or dictate the direction of Labour's campaign.
Mr Morgan is in a similar position to Jack McConnell. He is trying to win over voters disillusioned by the Westminster government.
But he has taken a different tack. A Labour source said that Mr Morgan was "undoubtedly" the face of the campaign in Wales.
The insider said that Mr Morgan had not taken part in any formal debates with his Plaid Cymru, Liberal Democrat and Conservative rivals but this was because no-one had asked him to do so recently, not because he had taken a decision to avoid debates.
BUT AT LEAST HE'S TOUGH ON AIRGUNS
MINISTERS may press for a ban on airguns if legislation restricting their sale and use proves ineffective, Jack McConnell said yesterday.
But police chiefs are to be given the chance first to show that the reforms they pressed for are working.
Mr McConnell told MSPs at First Minister's Questions: "This month the justice minister and I will meet police forces to ensure they immediately move to implement the new laws.
"We will monitor how they do it, and if that is not successful in the longer term, of course we keep open the option of further discussions with them, moving towards registration or bans."
He later told Tommy Sheridan, the Solidarity MSP: "I believe it would be wrong to rule out a total ban on airguns."
Mr McConnell also said there was a "very strong case" for seatbelts to be fitted to trains in the wake of last week's rail crash in Cumbria.
However, rail experts said seats would have to be strengthened, making them more of a danger to passengers, and lap belts would increase injuries. Research on car-style, three-point belts is due this year.
Time to step into the spotlight and accentuate all that is positive
EIGHT things that Jack McConnell needs to do to rescue the Labour Party's May election campaign, writes Hamish Macdonell, are:
1 Start grabbing the headlines. So far, the main anti-SNP speeches have been delivered by Tony Blair and Gordon Brown. If Mr McConnell hopes to persuade Scots he should be trusted with a new term as First Minister, he has to start taking over from the Prime Minister and the Chancellor as the main speaker in the Labour campaign.
2 Start leading the campaign. The last two main Labour election press conferences have featured five Scottish Labour figures and no Mr McConnell. He needs to start leading, and be seen to be leading, the campaign.
3 Start debating with Alex Salmond. The Nationalists are scoring points every time Mr McConnell turns down an opportunity to debate with the SNP leader.
He has to swallow his pride and reverse this decision.
4 Stop focusing on negative tactics over independence. The Scotsman poll this week shows that voters are starting to differentiate between the SNP and independence, realising they can vote for the SNP without this leading to independence.
Labour's tactic of focusing on the perils of independence is harming support for independence but is not denting the SNP lead.
5 Portray Labour as the best party of government in Scotland. Mr McConnell has to start showing why a vote for Labour is a positive vote, not a negative vote. He has to set out a clear vision for the next four years under Labour. So far, the Labour message has been overwhelmingly negative, warning why voters should not back the SNP rather than a giving a clear, positive case to vote Labour.
6 Take control of the campaign from London. It is clear that the national Labour Party, based in London, is playing a key role in deciding the direction of the campaign. Sending strategists such as Downing Street adviser John McTernan up from England and deciding policy in London will not give the Scottish Labour Party the flexibility and responsiveness it needs to take on the SNP with any success.
7 Improve morale among the Labour candidates and staff. A sense of pessimism has started to seep into the Labour campaign, driven by recent poll findings.
It is up to the leader to give party workers the belief that they can and will win the election. If that requires a round of private pep talks and motivational speeches, then so be it.
8 Start attacking the Liberal Democrats. The main threat to most Labour seats in the central belt, particularly in Edinburgh, will come from the Lib Dems. Labour needs to take them on. The party runs the risk of concentrating so much on the SNP, it allows the Lib Dems a clear run.