Scientists at the British start-up Satellite Vu took to the air over Leeds in an aircraft fitted with a high-resolution thermal camera, to identify buildings "leaking" heat.

Sky News was given exclusive access to the test flight, as scientists mapped an area of more than 115 square miles in just two hours.

To map the city from street level would have taken months.

Mike Kirstein, who operates the technology on board the aircraft, said it brought the energy crisis into sharp relief.

"We are getting insight into how people are using their energy," he said.

"You know they're being impacted by the energy crisis, the cost of energy at the moment.

"Some people unfortunately are not able to turn on their heating as much and we might be able to see some variation from building to building."

The images are colour-coded to show how much heat is being given off by objects.

Roads, with their thick asphalt and concrete beds, warm up the most during the day and retain that heat into the evening.

The houses are revealed in shades of blue - the lighter the colour, the more heat is being lost through the building's structure.

Properties showing up as black-blue are better insulated.

Jonathan Moss lives in a Victorian terrace in Chapel Allerton, a northern suburb of Leeds, with his wife and young daughter.

Although it has double glazing, the windows are 20 years old and are so poorly fitted that the blinds move when the wind comes from the wrong direction.

He also has a loft conversion with little insulation.

But the thermal image of his house was still an eye-opener.

"Sometimes your money's got to go somewhere else," he said.

"It's about all the other things and not having enough disposable cash to make investments.

"Changing windows and doors isn't that cheap. And sometimes it's about getting food on the table.

"But I think raising awareness (on energy efficiency) might be a good thing because it just put keeps in people's consciousness.

"It's a nudge."

That's exactly why the MCS Charitable Foundation funded the aerial survey in Leeds. They are working with the city council to raise awareness about the impact of wasted heat on energy bills.

It hopes stark images of homes that are losing more heat than surrounding properties will spur people into fitting more insultation.

Richard Hauxwell-Baldwin, the foundation's research and campaigns manager, said: "We know these houses are leaky and we need to solve the problem.

"We need to retrofit many more properties than we are at the moment - and a benefit of the thermal camera technology is that it helps local authorities pinpoint where they need to channel their efforts to make the most impact."

Around 29 million homes need an upgrade to their energy efficiency. The average house in the UK loses heat three times faster than a property in Germany.

Part of the problem is that the industrial revolution started earlier in the UK and many houses were built by the Victorians for people moving into urban areas.

It is only recently that the energy and climate crises have made people aware of just how expensive and inefficient older homes are to heat.

Satellite Vu is about to put its technology in space. The first of eight satellites will be launched in June, gathering data on energy use in any building, anywhere on the planet.

Once all the satellites are in orbit they will fly over the same region several times a day so energy use can be tracked.

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Natalia Kuniewicz, from the company, said they will allow detailed analysis of which production lines in a factory are operational, or verify whether nations are keeping to commitments to turn off coal power stations.

"With a thermal satellite you will be able to recreate a mosaic of all human activity in the world.

"So whenever you turn on the heating of your house, that's one thing.

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"But then also when there is congestion in traffic, you might be also able to see how many cars are stuck in traffic.

"And obviously there are also natural catastrophes that we might be able to see.

"For example, when it comes to a wildfire, we will be able to see the speed it is spreading, but also in what direction it's going."