New mountain Mynydd Graig Goch is on the far left (Picture: 'Envirodata-Eryri')
A Welsh hill has been upgraded to a mountain after three walkers found its official measurement was just too low.
Mynydd Graig Goch in Snowdonia was originally put at 1,998ft (609m), just short of the magic 2,000ft (609.6m) that qualifies as a mountain.
But the walkers found its true height is six inches over 2,000ft (609.75m).
Their efforts have echoes of the 1995 film set in Wales which starred Hugh Grant as The Englishman Who Went Up a Hill But Came Down a Mountain.
In director Chris Monger's quirky comedy, based on a true story, a Welsh community fought the attempts of two English cartographers to downgrade their local mountain to a hill.
Making a mountain out of a foothill
Welsh pride in its rugged landscape has triumphed again.
Now it is hoped that Ordnance Survey will alter its maps after the discovery by John Barnard, Myrddyn Phillips and Graham Jackson.
Welsh peaks have attracted tourists for generations, and its latest mountain takes the total number at or above 2,000ft to 190.
Before the survey, however, the country only had three hills at 1,998ft: Mynydd Graig Goch and Craig Fach, both in Snowdonia, Gwynedd, and Mynydd Troed near Crickhowell, Powys.
The three were confident Mynydd Troed was a hill, but suspected at least one of the peaks under scrutiny in Snowdonia was a mountain.
Using "state-of-the art" equipment supplied by Swiss firm Leica Geosystems, the trio used satellite positioning to gauge the height of the hills in Snowdonia.
Their survey confirmed that Craig Fach was a hill, standing at 1,997ft (608.75m), but further research showed Mynydd Graig Goch, at 609.75m, was slightly above the 2,000ft minimum for a mountain.
"It's fantastic. Nothing like this had happened before," said Mr Phillips, from Welshpool, Powys.
"We're very pleased our survey has proved Mynydd Graig Goch is a mountain and not a hill.
"Ordnance Survey has agreed to update its maps (on the internet) straight away, but it might take a bit longer to correct the paper maps."
Mr Phillips said the trio took on the task because they wanted to check the facts.
But he said Ordnance Survey spot height measurements had a margin of error of plus or minus 3m (9ft 8.8in) so it was hard to argue that its original measurement was wrong.
The three spent two hours taking 7,000 readings on Mynydd Graig Goch as part of the survey on 11 August, and the rough weather played its part too, said Mr Phillips.
"Winds between 40 - 50 mph (64-80kph) made things quite difficult for us and it rained, but it was worth it."