THE Scottish Greens are embroiled in a bitter row over an alleged ballot irregularity in the contest that selected their co-leader as a Holyrood candidate.

At an emergency meeting of the party's national council today, senior figures will call for a re-run of the internal selection that saw Maggie Chapman come first on the North East regional List.

Activists are concerned that a secret formula was used by the party that resulted in Chapman's name being put at the top of the ballot paper.

Party officials have suggested "investment" in "mediation" may be required to heal the growing rift.

The Scottish Greens are tipped to increase their MSP tally from two to around 10 next year and secure representation in all eight regions.

There was a big demand for candidacies for the regional Lists and Chapman, an Edinburgh councillor and party co-convener along with Patrick Harvie, got the top spot in the North East.

It emerged last week that a petition had been circulated calling for her to be deselected amid claims she was a "carpetbagger".

Chapman recently announced she would resign as a councillor in the Capital.

The Sunday Herald can reveal that a separate submission has been tabled for today's national council in Perth for the entire North East ballot to be rescinded.

In each regional contest, members received a list of candidate statements and a ballot paper.

The order of the candidates was assumed by party members to be chosen randomly.

"The statements are not in alphabetical order but are in the same order as candidates appear on the ballot paper", the official ballot document stated.

Having your name first on the ballot can be deemed to provide an advantage.

In the 2007 Holyrood election, the SNP outfoxed the other political parties by describing itself as "Alex Salmond for First Minister" on the regional List, which meant it was the first name alphabetically.

In the Greens' North East contest, Chapman was first in the candidate pack and the first name on the ballot.

This has prompted suggestions of favouritism, which have been denied by the party's ruling Elections and Campaigns Committee (ECC).

"The submission implies that the placing of Maggie Chapman at the top of the ballot list was done by something other than random selection. Unless there is evidence that this occurred then there is no option but to dismiss this," the committee's official response states.

However, this newspaper can reveal that the ordering on the eight regional Lists was determined by a formula, rather than random selection.

On every List, the candidate statements were alphabetised by the third letter of their surname.

In the North East, this meant Chapman was the first of twelve candidates, while rival Debra Storr was eighth and Aberdeenshire councillor Martin Ford ninth.

The only exception to the formula was for surnames beginning with "Mc" or "Mac", where the procedure kicked in after these letters were excluded.

It is understood the ballot rules were a matter for a Standing Orders sub-committee.

Sources say the formula would not affect races affecting well known MSPs such as Harvie or John Finnie, or help no-hoper candidates, but could provide an advantage in tight contests.

One insider said: "Why base it on the third letter of every surname? Why not the second letter, or the fourth? It looks like a complete stitch up."

Ahead of today's meeting, the ECC argued that the submission to rescind and rerun the ballot should be "rejected", although the committee accepted there were "aspects" of the selection process that the party needed to "reflect on for future".

The ECC also claimed a re-ballot would damage the party's credibility and cost at least £6,000.

On the separate petition to deselect Chapman, the ECC said such a move would be "highly divisive".

The ECC has instead aired three solutions: a "clear the air" session between North East activists and committee convenors; one-to-one conversations between Chapman and key local members; and "investment" in mediation.

Chapman is said to be part of a leftist grouping inside the Greens that includes Peter McColl and former MSP and ex-Militant activist Mark Ballard.

A spokesperson for the Scottish Greens said: "This is an internal matter and will be discussed tomorrow."

Chapman could not be reached.