last year for £100m.

Data on the number of deaths in air accidents globally also shows that there has been a decrease over the same period, albeit with spikes in some years reflecting major air disasters.In 2014, two such events contributed to a significant spike.

In March, Malaysian Airlines flight MH370 disappeared as it travelled from Kuala Lumpur to Beijing with 239 people on board. In July, another Malaysian Airlines plane, MH17, was shot down by a Russian-made missile over eastern Ukraine, killing almost 300.Data sets such as this are inclined to see sudden, large fluctuations, Prof Sir David Spiegelhalter, Emeritus Professor of Statistics at the University of Cambridge, told BBC Verify."If you count fatalities rather than accidents it's bound to be extremely volatile and sensitive to a single large accident," he said.

"Random events do not occur evenly - they tend to cluster. So unfortunately we can expect aircraft accidents to be appear to be connected, even when they are not."Regarding the series of high-profile accidents over the past few months, Ismo Aaltonen, formerly Finland's chief air disaster investigator, told BBC Verify they are not an indication of a decline in aircraft safety.

"It's very unlucky that we had this period of many different kind of accidents, but people should not draw any conclusions based on this because they are such different cases," he said.

He noted that some incidents over the past few months were unforeseeable, citing an Azerbaijan Airlines flight which crashed in Kazakhstan in December afterThis "mixed reality" experience "squeezes the training continuum" for fighter pilots, says the firm's CEO Timo Toikkanen, because they no longer have to travel long distances to complete war simulations in giant aircraft hangers, which are expensive to power and run. "You can do 99% of the same [training] inside of the headset."

The start-up had already attracted heavy investment prior to Russia's invasion of Ukraine, and started working with medical research companies and car manufacturers.But Mr Toikkanen says the start of the conflict and Finland's admission to Nato a year later "just kind of put everything on steroids" in terms of interest in its defence offering.

Since March 2022 the company has raised more than €50m (£42m; $54m) in additional funding.Mr Toikkanen says that before the war technologies that could be used by military forces used to be "kind of a red flag" for investors concerned about social and environmental responsibilities, and Varjo's executives would "tiptoe around" that side of the business when seeking funding.