Alex Salmond has set his sights on the SNP winning 20 seats at the next general election, which could result in the party holding the balance of power in the Commons.

The First Minister, in a typically robust speech to the SNP's spring conference yesterday, said that such a block of Nationalist MPs - 14 more than they currently have - could hold the whip hand over the next Conservative or Labour government, particularly one without an overall majority.

While the SNP would not contemplate formal coalition with either party, Mr Salmond said that such an SNP presence in the Commons would be able to exert influence and bring an end to the Government's “unreasonable behaviour” towards Holyrood.

He cited as examples indications from the Treasury two weeks ago that any attempt by the SNP to introduce a local income tax would be illegal under the terms of the Scotland Act and the refusal by Westminster to give Scotland a share, under the Barnett Formula, of Olympics regeneration funding in London.

“We are moving into a period where the balances of power can be fundamentally changed ... I say let us build a Scottish block of at least 20 MPs at Westminster, ready willing and able to defend our Scottish Parliament and our people. If we can achieve that ... we can make Westminster dance to a Scottish jig,” Mr Salmond said.

While SNP leaders are coy about specifying which seats they will be targeting, it is understood that they will not just focus on Labour-held seats, such as Dundee West, Ochil and South Perthshire and Stirling, but also want to take Lib Dem constituencies, such as Argyll and Bute. While the target may appear over-optimistic Mr Salmond said that at last year's

Holyrood election the SNP achieved a similar target and gained power in Scotland for the first time.

But opponents will look to evidence that since devolution Scottish voters use their vote diferently in a Holyrood election from how they vote in a Westminster election.

Mr Salmond also used his speech to predict that by trying to “lay down the law” to the SNP in devolved areas, such as local government finance, Gordon Brown would cause support for Scottish independence grow.

Mr Salmond said that Labour had “lost its way, forgotten its values and abandoned its roots.” He recalled that Labour MPs had celebrated last year when Gordon Brown, as Chancellor, had abolished the 10p tax band. The move, he said, had left 500,000 Scots households worse off. “They look less happy now that their seats are at risk,” Mr Salmond added.

The First Minister also attacked the claim made by Mr Brown at Scottish Labour's conference three weeks ago, that an independent Scotland would be a diminished country unable to wield influence to combat global challenges such as terror and climate change and world poverty.

“As our world becomes ever more inter-connected in terms of trade, international relations, the environment and security, the case for nations having a voice at global level becomes ever more compelling. It is by becoming independent that nations can maximise their influence in an inter-dependent world,” he said.

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