This is disgraceful. Three of Scotland’s biggest airports are owned in offshore tax havens.

When we use Scotland’s airports, we have to pay through the nose for everything from parking to food. But now it turns out that, instead of putting our cash back into the economy by paying their taxes, Edinburgh, Glasgow and Aberdeen airports are funnelling that cash into tax havens like the Cayman Islands and Jersey.

David Cameron promised to crack down on British tax havens -- but he failed. Now Theresa May has promised the same, and we urgently need to ramp up the pressure and make sure she actually delivers on that promise.

Tell Theresa May to demand transparency from British tax havens!

While ordinary people have no choice but to pay what we owe to society, corporations can wheedle out of it by using offshore tax havens. And the problem is rife. An investigation by Herald Scotland has shown that even our airports are at it -- with Edinburgh, Glasgow and Aberdeen airports all being owned or part-owned by companies registered in the Cayman Islands and Jersey.

Our airports used to be publicly owned -- and with good reason. They’re a strategic part of our transport infrastructure. But, in 1987, Margaret Thatcher privatised the British Airports Authority. And now many airports have set up complex corporate structures in secretive offshore jurisdictions -- meaning we no longer know who’s making key decisions about Scotland’s transport infrastructure, or in whose interests those decisions are being made.

The SumOfUs community has been at the forefront of clamping down on tax dodging. Because of SumOfUs members like you, we’re pursuing a groundbreaking case against HSBC for helping Britain’s richest evade tax. And for this, we made front page news.

But we need to do more. If we want our airports to work in the public interest, we need to know exactly who owns them, and exactly what their corporate structure is. David Cameron promised to get transparency from Britain’s tax havens, by demanding they list companies' owners in a public register. It sounds like a small step, but this increased transparency would go a long way to stopping corporations’ use of shell companies registered in tax havens to avoid paying taxes.

Cameron failed. So now it’s down to us to make sure his successor, Theresa May, makes good on the promise.