Scottish Nationalists have called on the Edinburgh executive to prevent the commercial growing of GM crops north of the border.

Last week, ministers in the Holyrood parliament backed Westminster's approval for growing GM maize, although GM-free areas of the country would be created "where there is evidence of increased harm".

Speaking ahead of the debate SNP environment spokesman Roseanna Cunningham said it would "pressure the executive into resisting Downing Street's pro-GM agenda".

"Last week's GM announcement was met with outright opposition from Welsh ministers, here in Scotland the response was feeble," she said.

"The public is overwhelmingly opposed to GM, yet Scottish ministers refused to use their powers to block it.

"Now we learn that Whitehall is planning to try to compel Scotland and Wales to accept Downing Street's pro-GM agenda.

"The parliament has to now step in and make clear that ministers must not capitulate in the face of pressure from London."

Cunningham also called on the Liberal Democrats to back the SNP motion, saying the debate would "put an end to Lib Dem fence-sitting and force them to come clean".