“Almost certainly” to be a result of human activity, says SFRS (Scottish Fire & Rescue Service). That might mean sheer stupidity (open fire or single use BBQ, abandoned when it was still hot enough to set the vegetation alight underneath) or deliberate malicious action. The fire was under control by next morning.
Fires have been a big problem up north this year: huge areas damaged in Aberdeenshire (I think it was), and in Galloway. Rangers (where there are any) call out the fire service if there’s a risk, but people just relight the fires once they’ve gone. There’s a petition with Scottish government to ban single use BBQs (which heat the vegetation underneath, so a fire can flare up next day) but it’s not looking likely to succeed.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.