Everyone in the SNP has a "broad smile" at the thought of wielding an influence in Westminster, former leader Alex Salmond has said.

Mr Salmond, who took Scotland to the brink of independence last year, said the SNP has set the General Election campaign alight with its post-referendum surge and polls predicting a landslide for the party in Scotland.

But speaking after a hustings event in Aberdeen organised by Oil & Gas UK, Mr Salmond said he is taking nothing for granted.

"Everybody in the SNP has a broad smile at the moment because our very positive message for the future of Scotland, having real influence for the first time since the 1970s in the Westminster Parliament, is catching this campaign alight," he said.

"Despite the fact that we are very pleased with the way things are going, there is not a shred of complacency.

"We know we've got two weeks to work really hard to maximise that positivity we're getting in the communities and on the doorstep, and turn it into a real result for Scotland and that's what we intend to do."

Mr Salmond joined Chief Secretary to the Treasury and Liberal Democrat candidate Danny Alexander, Labour's Anne Begg, Alexander Burnett for the Conservatives and Daniel Yeats for the Greens.

The oil and gas industry supports about 450,000 jobs in the UK, around 45% of them in Scotland.

Oil & Gas UK says the offshore industry has become uncompetitive, suffering from spiralling costs and high taxes, and there is a risk that many older fields will become increasingly uncommercial and will be decommissioned as a result.

A new regulator, the Oil and Gas Authority, has been established to maximise the economic recovery from the UK Continental Shelf.

Speaking after the debate, Mr Salmond said: "This has been a very positive session with Oil & Gas UK.

"What I was saying today is that if we are going to take advantage of the huge opportunities there are to come over the next 50 years in the North Sea, then we have to establish a real community of interest between all of the people that are going to benefit from that long-term future, and that includes workers as well as oil companies, it includes academia as well as the broader community.

"Promotion of that, and getting people to realise that we have a shared interest in the long-term future of the North Sea, seems absolutely crucial and it's even more crucial in hard times like we're having at the present moment than in good times we've had in the past, and indeed will have in the future again.

"That community of interest should be one of the central messages from this oil downturn as we look to the future to re-establish prosperity in this industry."

Mr Alexander, candidate for Nairn, Badenoch and Strathspey, told the Spotlight on Energy debate that the North Sea industry needs to be handled as an economic asset, not a tax asset.

Speaking after the hustings, he said: "For a very long time people only saw the North Sea oil and gas sector as a resource to generate taxation but the truth is that we're in the period where we've got to work really hard to extract the last remaining drops of oil and gas from the North Sea to maximise the economic recovery.

"The focus needs to be on the North Sea as a job-creating asset, as an asset that is helping us to secure our energy independence, and that means government accepting that there's going to be much less tax coming through the system in future.

"That's why a few months ago I announced big reductions in a number of the key headline taxes and why the direction of travel in taxation has to be over the long term in a downwards direction because that's the only way to make sure that people see the North Sea as a place they want to invest, to put their money, to go and explore, to take risks."

He added: "In order for the North Sea to thrive and prosper through this difficult period and into the future when the oil price recovers, we need to have stability.

"We need stability in terms of the fiscal situation, we need to make sure the new regulator works, but we also need to have stability in terms of Scotland's place in the UK and the UK's position in Europe, and we need to have a stable government for the UK too. The only party that can deliver that is the Liberal Democrats.

"People are in many cases frightened of what the SNP will do to the country, they are frightened of the instabilty that might emerge from the SNP holding the cable to the life support machine on a Labour government, or indeed what you might see if the Tories and Ukip work together."

Mr Alexander said SNP plans for full fiscal autonomy, where Scotland would have complete control of taxation and spending, was a "hugely dangerous proposition" for the whole of the UK.

New analysis from the Institute for Fiscal Studies (IFS) suggests that Scotland's finances would fall behind the rest of the UK's, leading to a budget gap of £9.7 billion by the end of the decade.

Mr Salmond said: "Two of the last four years Scotland has been in a better fiscal position then the rest of the UK.

"Over the last 30 years, if we'd had fiscal responsibility then Scotland would be sitting, like Norway, on an oil fund of £100 billion as oppose to sharing in the gigantic debts of the UK Government.

"I think people realise that the key to prosperity is to have the levers for economic growth.

"What creates revenue is jobs and investment and that's what the SNP are determined to bring to Scotland."

Aberdeen South Labour candidate Dame Anne said the industry is at a "crossroads" and what is needed is stability and a reduction in recovery costs.

She said: "The crossroads is whether the oil and gas industry actually collapses before we manage to get out all the oil that we could possibly get, or whether we have a slow, managed decline.

"We need to be careful that we can sustain the developments and the recovery through an oil price that fluctuates.

"We also need to make sure we don't lose the skilled people that have been made redundant as a result of the downturn here.

"Hopefully the price of oil will come up, and that with more exploration there is a future for North Sea oil and gas, so we have to make sure we've got the skilled people still in the area to take advantage of that."

She added: "I think what the industry wants is stability, political stability, fiscal stability - they would love stability in the oil price but that's one thing they are not going to get.

"Instead what we've got in this country is a lot of political instability. We've got the talk of perhaps another referendum, and we've got the SNP asking for full fiscal autonomy in Scotland which could mean different tax rates north and south of the border."

North East businessman Mr Burnett, Conservative candidate for West Aberdeenshire and Kincardine, said: "It's about listening to the industry. The industry is too big to be run by politicians. What we've seen in the last government is a government that has listened, they have delivered.

"They have come up here and I have attended meetings with George Osborne and other ministers. We've delivered £1.6 billion in the Budget, that's been welcomed by experts such as Sir Ian Wood and Oil & Gas UK.

"I think by showing ourselves as a party that understands the business, is prepared to listen to the business and then prepared to deliver, we have shown ourselves to be credible, and a credible choice going forward."

Green candidate Mr Yeats underlined the need to move away from a reliance on fossil fuels and for money generated by the energy industry to filter down to the city.

He said: "Individuals have benefited from high salaries and companies have benefited from renewed contracts but the infrastructure money that has come in to maintain the roads, social housing developments, that sort of thing, hasn't come to fruition.

"It's about proper planning legislation, or using existing planning legislation to see what we can do in terms of holding projects to account.

"So if they want to build new premises or invest in an area, there has to be social capital implications as well."