The Labour MSP who battled to legislate on corporate killing pledged yesterday that she would be back with her member's bill in the wake of the Stockline explosion.

ICL Plastics and ICL Tech were given fines totalling £400,000 on Tuesday over the factory gas explosion which killed nine people and injured 33 in Maryhill, Glasgow, in May 2004.

Karen Gillon, MSP for Clydesdale, took up the issue in association with the STUC following the Transco case in her own constituency, in which a gas explosion caused by a leaking main killed Andrew and Janette Findlay and their two children in their Larkhall home in December 1999.

Ms Gillon warned senior SNP figures who had backed her bill in opposition in the past that she would be watching to see if they reneged on that commitment.

She cited as grounds for suspicion a reply she had received from Kenny MacAskill since he became Justice Secretary, saying: "The Scottish government welcomes the Corporate Manslaughter and Corporate Homicide Act 2007 and we are now focused on working closely with the UK government to support its successful implementation in Scotland.

"We consider that this legislation addresses the identification problem identified by the Transco case. It also sends out a robust message to organisations that failure to meet their duty of care to employees will not be tolerated."

But Ms Gillon believes that the ministers' reply ducks the key issue, insisting: "The Stockline affair has moved all this debate on, not least because the punishment was so derisory." She said her instincts had always been for a UK solution as she was uneasy at the prospect of English workers or members of the public having less protection than their Scots counterparts.

Ms Gillon said she had been persuaded to withdraw her bill on the basis that Westminster legislation would work, but she added: "I see no reason why the Scottish Parliament should not lead the way on this, as we did with the smoking ban. It is clearly a justice issue and that is devolved."

Maryhill MSP Patricia Ferguson said yesterday she would back Ms Gillon if she resurrected her member's bill because UK legislation was disappointing. She added: "The opportunity is still there for that bill to come back in another form . . . I would support that."

Frank Maguire, of the trade union lawyers Thompsons, has worked with Ms Gillon from the outset of her attempts to legislate at Holyrood for a law on corporate homicide which would allow senior company officers to be punished for safety breaches.

He stressed that these were not concepts that were strange in Scots law. They existed in our civil courts and there was no good reason not to bring them into the criminal courts.

It was denied last night that ministers were backsliding on supporting tougher Scottish laws. A spokesperson for the Scottish Executive said it has welcomed the Corporate Manslaughter and Corporate Homicide Act 2007, which is due to come into force next April, and added: "The Cabinet Secretary has already made it clear that if the legislation was found to be wanting then we would consider what further steps should be taken."