The case for Scottish independence is being made by Westminster more eloquently than Holyrood ever could, Finance Secretary John Swinney told the SNP conference yesterday.

In a day of celebration of the Nationalist achievement in winning May's elections at both Holyrood and council levels, Mr Swinney had to make the most austere of ministerial speeches. In under three week's time he will have to explain his spending intentions.

But yesterday he told SNP delegates in Aviemore that the financial hand he had been dealt by Westminster appeared to be calculated to make the case for Scottish independence.

"We must show that we are governing well and that means we must deliver in the easy days and in the tough days," he said. "Before the election we set out clear financial plans and they remain central to our approach. We have £500m less for capital projects. Parliament voted for Edinburgh trams and we accept their decision. Respecting the will of Parliament does not come without a hefty price tag."

In the clearest signal yet that his budget will be austere, he said: "We don't always need to legislate or regulate. We just need to take the right actions."

He spoke of the future settlement as being £700m less than anticipated over the next three years, insisting: "We face the tightest financial settlement since devolution, of that there is no doubt.

"And at all this time when oil revenues flowing south into the London Exchequer are set to rise well into the next decade, even on dodgy UK estimates of an oil price that today is almost $20 a barrel below market value.

"If I did not know them all as well as I do I would have thought the UK government's spending review and budget report were an eloquent attempt by the UK Treasury to make the case for independence."

He claimed that "our black gold is filling the Chancellor's self-inflicted black hole. If there was ever a case for Scotland to be in charge of our own revenues and our own spending in the UK spending review we have just heard made that case as well as any of us could have".

Mr Swinney condemned the decision of the last administration to give away up to £100m annually on an "ill thought-out" decision to surrender funds from the Holyrood budget. "They did this by agreement with the Treasury. If that's what the last administration thought was meant by standing up for Scotland, then no wonder we have a new government in our country."

Mr Swinney will be making his full budget statement in less than three weeks from now so his speech yesterday was constrained by that. He promised that his ministers, Jim Mather and Stewart Stevenson, were already demonstrating a commitment to industry and tourism which gave a "clear route-map- for success".

The conference also committed itself yesterday to a call for a referendum on European reform in the wake of the latest treaty deal struck by Gordon Brown. Aides later made clear that the SNP stance would now be hostile, given the loss of fishing as a red line issue.

The motion stated: "Conference deplores that, despite the concerns of the Scottish fishing communities and the Scottish Government, the UK Government has refused to seek changes to the treaty text in relation to the competence over fisheries."

If Westminster faces any vote on the issue of allowing a referendum then SNP MPs will be committed to backing the principle of a referendum, but it was being stressed last night that without a change of policy on the fishing question the stance would be to oppose the new EU treaty.