I have fought all kinds of elections across all parts of Scotland. And I led from the front in the two big referendums that have been put to the people of this country – over independence and EU membership.

In nearly 20 years of campaigning, I have never seen a constituency by-election which is also a direct referendum on one of the big policy fights of the age.

Until now. Because the Aberdeen South by-election is exactly that. It is as close as I can imagine to a direct referendum on whether Scotland’s oil and gas industry has a future or not.

On one side you have the Scottish Conservative candidate, Douglas Lumsden – a man who has worked for 25 years in oil and gas before turning his attentions to serving the city, first as co-leader of the council and then as an MSP.

On the other side you have Labour and the SNP – which both have policies crippling the very industry upon which much of the economy of the North-East is based.

And the utter madness of the situation is the fact that, with the war in Ukraine and the conflict between the US and Iran, a safe, secure and reliable energy supply has never been more needed.

Other countries can see that. The government of Norway is in the midst of reopening three further oil fields in the exact same North Sea basin as the SNP government at Holyrood and the Labour government at Westminster are trying to run down.

Worse, Labour is helping fund Putin’s war machine by importing diesel and jet fuel produced by Russian oil at the same time as banning exploration licences here. It is utter madness.

Scotland and the UK desperately need economic growth, but right now a thousand jobs a month are being shed in the oil and gas sector. Good jobs. High paying jobs. And these jobs don’t just disappear by themselves without a ripple effect.

Aberdeen South voters know that every single job that leaves the sector has an impact on their city – whether that is the increase in For Sale signs in residential neighbourhoods or the closure of shops and restaurants that were just about hanging on, but now can’t make the numbers work.

It is a sin that the UK’s energy capital, powering the economy and keeping the country’s lights on for so many decades, is being treated like an embarrassing uncle by both the UK and Scottish governments – which would rather not have to acknowledge its predicament or talk about its challenges.

Well, the good voters of Aberdeen South will be heard tomorrow. They have the power to send a message that their city will not be ignored. That the energy industry needs listened to.

And they can send an MP to Westminster in Douglas Lumsden who will make himself a thorn in the side of anyone who dares to wish Scotland’s oil and gas industry would just quietly wither on the vine.

I have been out on the doors with Douglas multiple times during this campaign and I know the people across the constituency understand what is at stake. They understand, too, that Douglas gets it.

And they know that the SNPs sudden attempt to show a more friendly face to the oil and gas industry doesn’t hide the standing party policy of a presumption against new projects or a climate minister who refuses to back the development of Rosebank and Jackdaw fields.

They also know that, with Ed Miliband in charge of energy policy, Labour will not stop until UK oil and gas production ceases. It would rather buy products from abroad and have them shipped here than see UK workers develop a UK resource.

But there’s one more thing the voters of Aberdeen South know – that the winner tomorrow will either be the SNP candidate or Douglas Lumsden for the Conservatives.

Labour, Reform and Lib Dem are trailing far behind. The choice is a nationalist who would prefer to break up Britain than see a sensible energy policy keep oil and gas jobs in Aberdeen, or a Conservative candidate who understands the sector and would fight every day to be the industry’s champion in Parliament.

The Holyrood election a few weeks ago showed what can happen with a split in the anti-SNP vote. In the corresponding Scottish parliament seat, 6,000 voters cast their ballot for Reform (and nearly 3,000 each for Labour and the Lib Dems) and it let the SNP in through the back door, taking the seat by just 1,244 votes.

I know that Reform, Labour and Lib Dem voters didn’t want an SNP MSP by default but, by splitting the vote, that’s what happened.

And that’s why so many of the people in Aberdeen South have told me that they are willing to lend their vote to Douglas Lumsden, even if they aren’t natural Conservatives.

In this referendum on the future of oil and gas in the North East, they are voting for the champion who will fight for them.