ALEX Salmond will meet fierce resistance among his own MSPs if he insists on offering voters a "devolution max" option in the referendum.

The Sunday Herald understands that a majority of his parliamentary group instead want a straight vote on independence.

Although the UK and Scottish Governments have exchanged barbs over the timing and legality of a Holyrood-run plebiscite, the key disagreement is over the question to be put to voters.

Prime Minister David Cameron wants a "clear" question on independence, while Salmond has said he is open to devo-max also being offered alongside separation and the status quo. He said the extra powers option would have to be formulated by a party other than the SNP.

Devo-max is believed to involve handing over most taxation and spending decisions to Holyrood, while areas such as defence would be reserved to Westminster.

Salmond's critics believe he is floating the idea as a way of gaining a consolation prize should voters reject separation. However, it is understood that the stiffest opposition to devo-max on the ballot is likely to come from inside the SNP.

Party sources said there was little appetite for widening the options, with one senior MSP saying: "I think there's a majority in the group for just having a question on independence."

A second SNP MSP said: "The only person arguing for devo-max, as far as I can see, is Alex Salmond."

Another Nationalist insider said: "Most of the ministers, including Cabinet Secretaries, don't want to offer devo-max."

The source said having two competing constitutional options would be a "distraction" and divert energy from convincing voters about independence.

Nicola Sturgeon, the Deputy First Minister, appeared to move a step away from devo-max last week by saying the SNP's "preference" was a single question on separation.

Opposition parties have also stepped up their attacks on devo-max. David McLetchie, the Scottish Tories' chief whip, described the option as "the doodles of a few pamphleteers". And Willie Rennie, the leader of the Scottish LibDems, said a second constitutional change option was "reckless".

However, support for devo-max has grown among civic Scotland. The Scottish Council for Voluntary Organisations has made positive noises about extra powers for Holyrood, while devolution grandee Canon Kenyon Wright said excluding devo-max as an option would disenfranchise voters.

An SNP spokesperson said the party welcomed views on devo-max, adding: "As a party we are campaigning full square for independence."