Voters can see right through the ‘two-faced’ position of the SNP on oil and gas drilling, and new projects will never be categorically backed while John Swinney is reliant on the support of the Greens, according to the leader of the Scottish Conservatives.

In his final message ahead of the crunch Aberdeen South by-election taking place on Thursday, Russell Findlay condemned the Nationalists for claiming that Westminster will destroy the oil and gas sector when they previously introduced a ‘presumption against’ new licences.

Mr Findlay highlighted that the First Minister was reliant on Green support to vote down a Holyrood inquiry into the Peter Murrell scandal, and he said Mr Swinney will never be able to emphatically back new drilling while requiring the party’s backing.

Voters go to the polls in the constituency in a by-election which the Tories claim is a local referendum on the future of the oil and gas sector, amid widespread anger in the city about the approach taken by both the Labour and SNP governments.

Insiders say the vote, which was called following the resignation of former SNP Westminster leader Stephen Flynn when he was elected to Holyrood, is on a knife-edge between the Nationalists and the Tories in what is being billed as a two-horse race.

A by-election is also taking place on the same day in the Arbroath and Broughty Ferry constituency, with the SNP confident of holding the seat previously held by Stephen Gethins, who also switched to Holyrood.

Speaking on the eve of the voting, Mr Findlay said: ‘The people I speak to in Aberdeen can see right through the two-faced position of the SNP. The reality is this: John Swinney is completely tied to Nicola Sturgeon’s position, which is a presumption against new drilling. 

'There is no amount of spin in the world that will change that. That is his position because he is wholly reliant on the Green group at Holyrood saving his skin, and that is exactly what we’ve already seen with the Peter Murrell inquiry.

‘The reality is these two parties are joined at the hip, nothing has changed. We’ve got the SNP and then we’ve got the SNP B Team led by Ross Greer, and while he is reliant on them you will never ever get the SNP to change its position on oil and gas, which means this election is absolutely critical.

‘You can vote for the SNP who will kid on they are pro-oil and gas or you can actually back a pro-oil and gas champion in Douglas Lumsden.’

The Scottish Tories have been campaigning hard in a bid to win the seat and have been heavily supported by resources from the UK party, while Kemi Badenoch has made three visits during the by-election campaign.

Mr Findlay said the by-election is on a ‘knife-edge’ and he urged supporters of other pro-UK parties to back the Tories in the ‘two-horse race’.

He added: ‘Actually, for SNP voters in Aberdeen South who understand the critical juncture the industry is at, the right thing to do is to vote Scottish Conservative in this by-election to have a local oil and gas champion going down to Westminster and rattling Ed Miliband’s cage, because if you send an SNP MP down to Westminster they will be toothless and they will be silent, as we’ve seen with the previous SNP MP.’

Ahead of the vote, former SNP election candidate Fergus Mutch, who was the party’s head of communications, condemned its ‘betrayal’ of oil and gas.

Mr Mutch, who is now a partner at True North Advisors, told the broadcaster LBC: ‘The people in Aberdeen South do not necessarily see that they have a government on their side with the current UK government, which has expanded and extended the Energy Profits Levy, is talking about making it formal that no new exploration licences will be granted in the North Sea, and is bringing forward the end for that industry in which thousands of people make their livelihoods.

‘Meanwhile, the Scottish Government ... seems to be putting climate ambition ahead of people’s jobs. I think people rightly in Aberdeen see that as a bit of a betrayal.’ He also accused the SNP of ‘woolly words around climate compatibility’ regarding new licences and projects such as Rosebank and Jackdaw.

SNP candidate Richard Thomson said: ‘The SNP stands to protect Scotland’s workers, Scotland’s economy and the resources our great country has been blessed with – that is exactly why we will not let Westminster destroy our oil and gas industry.’

Scottish Green candidate Jorg Shelton-Eckstein said: ‘For too long, Aberdeen and the North-East have been ... treated as a playground for oil and gas companies that have profited from our city and exploited our workers.’

Meanwhile, the Scottish Government has said in response to a freedom of information request that there is ‘no relevant correspondence to or from Scottish ministers’ about the publication of a new energy strategy so far this year. 

The Tories said this means ministers are not working on a new approach and the previous presumption against new oil and gas drilling has not changed.