BEER and sandwiches were nowhere to be seen as SNP and Greens MSPs sat down for crunch budget talks.

As public service funding and tax arrangements teetered on the brink, both parties, had to make do with water. Perhaps it was another sign of austerity biting.

More than a dozen meetings took place as the two sides wrestled over detail. On one occasion Finance Secretary Derek Mackay conducted negotiations over the phone with Patrick Harvie, the Greens co-convenor, after the minister's childcare commitments meant a planned meeting was cancelled.

It was on the morning of last Wednesday's budget vote that the six Greens MSPs finally confirmed they would support the Government's spending plans for 2018-19.

"A week or two before I wouldn't have been willing to bet more than a pint of beer on the outcome either way," admitted Harvie, in a pointed reference to the missing drink from the proceedings.

Uncertainty surrounding the budget is an annual fixture since the SNP found itself a minority government again, dependent on opposition parties to get its spending plans through parliament.

This year Harvie and fellow Green MSP Mark Ruskell were up against Mackay and Joe FitzPatrick, the minister for parliamentary business.

Mackay is viewed as a "very political" finance secretary and a "serious party man" due to his other role as SNP chairman. The lesser known FitzPatrick is more of a "backroom figure".

Harvie says the talks "never got angry" but admits to "moments of frustration" over funding cuts.

"If anyone just digs their heels in then we would be heading for a dysfunctional five-year term", he says.

For anyone in any doubt about what was at stake, remember that in 2009 the then First Minister Alex Salmond threatened an early election when his minority administration's budget was defeated, although a rehashed budget was later approved.

But nine years on and well into the austerity era, what was it that led the Greens to prop up the SNP, while Labour, the Tories and Lib Dems voted against the budget?

"What struck me was that the last time we had a minority government from 2007 to 2011, every time I went to negotiate with John Swinney, I saw other parties coming in and out." Harvie says. "Yes this time I saw no sign of other parties at all."

Speaking from the relative calm of his office in Glasgow, he claims the Greens were left to shoulder the responsibility for trying to salvage a budget deal.

"My deepest frustration is that the same people arguing that the independence referendum was divisive are the same ones who refused to negotiate", he says of Labour, the Tories and Lib Dems.

Opponents have accused the Greens of milking their 11th-hour announcement of support for the budget for dramatic effect. However, Harvie insists the Greens had been willing to sink the spending plans.

"Some limits were put on the discussions some months before the budget began," says Harvie. "We took a motion to the Scottish Green conference and asked it to bind our hands so that we could not support cuts," he adds.

He insists he and Ruskell warned Mackay that they would vote against the budget unless it met "key tests" over anti-austerity.

It was the Finance Secretary's pledge of an additional £170 million for local councils that swung it for the Greens before the all-important vote Holyrood vote.

However it's a process Harvie says the Greens are not prepared to go through again. They have insisted council cuts must be kept off the table from the beginning of next year.

"There must be a change in approach as we won't have another annual squabble about how much there is for local government," Harvie adds.

Labour MSP Neil Findlay slammed the Greens over the budget agreement, accusing Harvie and his party of selling "those who rely on council services down a green river".

He added: "Patrick Harvie claims to have saved local government. He should tell that to councils of all political stripes that will be forced to cut services because of the budget presented by Derek Mackay and supported by compliant members of the Green party."

For the Greens, after Wednesday's parliamentary vote, there was a celebratory night of beer and pizza.