THE SNP had to bail out the Yes campaign to the tune of £825,000 at the end of the independence referendum, it has emerged.

The party transferred the huge block of funding to Yes Scotland Ltd in three tranches straddling September 18, according to newly released Electoral Commission records.

The files show the SNP donated an initial £275,000 just eight days before the vote.

The party then donated another £100,000 on November 7 and a further £450,000 ten days later, when Yes Scotland was settling its invoices.

Without the cash, Yes Scotland, which also included the Scottish Greens and Scottish Socialists, could not have paid its bills, insiders admit.

Yes Scotland and the SNP previously insisted the campaign was "self-financing".

In contrast, the unionist Better Together campaign stopped taking donations in July because it had all it could legally spend and took no money from a political party.

A senior SNP source told the Sunday Herald: "The party has never been upfront about this."

Overall, the SNP gave Yes Scotland more than a third of its £2.4m income over the last leg of the referendum, known as the regulated period.

Only Ayrshire lottery winners Chris and Colin Weir gave more, donating £1m.

The SNP also donated £343,000 in start-up costs to Yes Scotland in mid-2012, making its total support almost £1.2m. The party spent another £1.3m on its own campaign.

Two years ago, then Yes Scotland chief executive Blair Jenkins stressed that, aside from SNP seed money, Yes Scotland would pay its own way.

He said: "I wanted Yes Scotland to be self-financing and within about four to six weeks after starting, Yes Scotland was self-financing.

"[It's] very important to me there's a distinction made between the SNP and Yes Scotland.

"The campaign has to be self-financing so it's seen as a national movement which embraces a far wider range of people than just the SNP."

However the scale of the SNP financing reinforces long-running criticism - dismissed by Jenkins as a "smear" - that Yes Scotland was an "SNP front" bankrolled and staffed by the party, rather than a genuine grassroots movement.

Stan Blackley, Yes Scotland's ex-deputy director of communities, said the outfit always struggled for money as it failed to employ experienced fundraisers.

"Yes Scotland was meant to be cross-party and self-sustaining, but there was a naive view that the great and good would just reach into their pockets for it.

"It's no surprise to hear it was in need of finances when it came to a conclusion."

A key problem was a lack of donations from businesses.

Both campaigns raised similar sums from individuals in the regulated period - £1.6m for Yes, £1.75m for No - but Better Together also raked in £711,000 from companies against Yes Scotland's £20,000.

This was in spite of Yes Scotland hiring one of Alex Salmond's former special advisers, Colin Pyle, to liaise with the business community.

A Better Together source said: "One of the most ridiculous things about the Yes campaign was Blair Jenkins feigning mock outrage whenever anyone suggested they were just an SNP front. Now everyone can see that was just another piece of nonsense."

A Yes Scotland source insisted: "It was always the case that, as the largest stakeholder in the Yes movement, the SNP would be responsible for funding to a substantial extent. There was no question of being bailed out. The campaign ran smoothly and it was well-funded."

An SNP spokesperson said: "Obviously the SNP would support Yes Scotland."

Both Yes Scotland and Better Together spent £1.42m in the regulated period, while Labour spent £732,000, the Tories £356,000, and the LibDems £188,000.