The highly anticipated results of four heightings carried out in May and July revealed that Sgurr nan Ceannaichean, north of Glen Carron in the Highlands, fell just one metre short of the prestigious 914.4 metres (3000ft) needed to secure Munro status.

Although current Ordnance Survey maps record the height of the summit at Sgurr nan Ceannaichean as 915m, some 75cm clear of the threshold, when the peak was measured using GPS technology on July 15 this year by a heightings team from the Munro Society the result came out at just 913.43m.

Its summit can be climbed either directly and steeply up the north-west shoulder, or via the long and uniform slopes of Moruisg, whose westwards ridge offers spectacular views both north, to the Torridons, and south to the Loch Monar hills.

But Sgurr nan Ceannaichean will now be reclassified as a Corbett – a mountain reaching between 609.6m and 914.3m – and future editions of the OS maps will be edited.

The change reduces the total number of mountains in the Munro category from 284 to 283.

Of the three other mountains heighted during the summer, two – Beinn Teallach, north of Loch Laggan, and Ben Vane, north of Loch Lomond – retain their Munro status.

Beinn Teallach measured 914.6m, and Ben Vane a more comfortable 915.76m.

The fourth, Sgurr a’Choire-bheithe, above Barrisdale in Knoydart, came out at 913.32m and will retain its classification as a Corbett.

For true aficionados, the significance of yesterday’s revision cannot be underestimated.

Ever since the Scottish mountaineer, Sir Hugh Munro, first identified those summits over 3000ft for an 1891 heightings table, it has become a rite of passage for hardcore hillwalkers to collect the set – so-called “Munro bagging”.

So, for those still striving to climb every Munro in Scotland, the task has just become one mountain easier, while those who have sweated and struggled to the summit of Sgurr nan Ceannaichean now know that – but for a one metre shortage – they need not have bothered.

“There were far too many of them already,” joked Dr Iain Robertson, heightings co-ordinator for the Munro Society. He added that while he did not believe the loss of one Munro would make much difference to the overall feat of Munro-bagging, retaking measurements – especially with advanced technology – was important.

“We hope we are carrying on a tradition set by Hugh Munro – he was very into accuracy. So I think it would please him,” he said. “And Inaccessible Pinnacle on Skye still remains the major challenge; that’s the one that stops some people completing it.”

Questions were raised, however, about the use of amateur surveyors for the heightings. Graham Jackson and John Barnard, experienced climbers and members of the Munro Society, led the surveys with the backing of professional surveyors CMCR Ltd – which loaned the necessary equipment – after it became clear the society would not be able to afford to hire professionals to carry out the heightings for them.

But Mr Jackson dismissed any doubts. “We used the same equipment and followed exactly the same scientific methods, so it’s not a question of amateur versus professional,” he said. “I would expect anyone else going up there with the same equipment they would come to the same result. It’s been verified by Ordnance Survey.”

Graham Little, from Ordnance Survey, added: “What struck me was just how close those measurements are to the original taken in the sixties and seventies using aerial photography and imagery. It’s astonishing.”