LABOUR'S Holyrood rebellion on Iraq was not intended as a leadership challenge against Jack McConnell but was meant to strike a blow for honest and open debate, it was claimed last night.

Susan Deacon, the former health minister, insisted her decision to table a parliamentary motion was a reflection of last weekend's mass protests and the reaction among Labour's grassroots, and was not to be seen as an attack on Mr McConnell's leadership.

The issue of war with Iraq threatens to split the Labour party and damage its performance in the Holyrood election.

Labour MSPs were drilled by Mr McConnell on the issue on Tuesday at the parliamentary party's weekly meeting in Edinburgh and a spokeswoman claimed there had been no ''disquiet'' from MSPs.

However, Ms Deacon's motion, tabled yesterday and signed by 29 MSPs, including six from the Labour benches, challenged that idea. It also called on the Scottish Parliament to recognise ''the strength of public opposition to any support for unilateral US military action against Iraq''.

It cited as evidence the mass protests that took place in Glasgow and London last Saturday, involving millions of people.

It warned that ''a pre-emptive attack on Iraq is neither necessary nor justified and would be in contravention of international law''.

Last night, Ms Deacon, MSP for Edinburgh East and Musselburgh, dismissed suggestions that she was laying down a marker for a future leadership challenge if the Iraq issue led to a poor Labour showing in May.

She said: ''That is just such absolute nonsense. It is pathetic rubbish. Previous motions on this subject and other related international issues have not attracted this accusation.

''The nature of politics is that you come under fire in many circumstances, but politics should not be a popularity contest. We live in a day and age when the public has become ever more sceptical, but many of us entered politics precisely because we have view on issues of this kind.''

However, she must now face the wrath of many of her colleagues who accepted the stricture from Mr McConnell, at the tail-end of the parliamentary group meeting, that everyone should rally round the pro-war position of Tony Blair.

Ms Deacon denied she had snubbed the first minister by tabling her motion the morning after the appeal for unity.

She said she believed her motion was in touch with public opinion, but it touched a raw nerve at the parliament.

The SNP immediately backed it, as did several prominent Liberal Democrats. The LibDems then began to backtrack, in consultation with the party in London, and later tabled their own motion.

While many Labour MSPs loyal to Mr McConnell were enraged by what Ms Deacon did, she gained the support of Scott Barrie, Bill Butler, Pauline McNeill, John McAllion, Kate MacLean and Elaine Smith.

In Westminster, Conservative peers stepped up the pressure, demanding ministers give a House of Lords statement on the Iraq crisis.