Unit members from across the Borders would have been winding down towards bedtime on Tuesday evening when their team pagers sounded the alarm shortly after 9pm.
Two male walkers, both aged in their 60s, had set off from the Ingram Valley in Northumberland for a high-level walk in the Cheviots.
But, in dense clag and very limited visibility, they became disorientated and were forced to try to use a fence as a navigational handrail.
“Unfortunately it was a relatively new fence which wasn’t marked on their map, which served only to add to their confusion,” said a unit spokesman. Several hours after dark, they managed to pinpoint their position at a finger-post on Cairn Hill, just a few hundred metres west of Cheviot summit.
By this point, however, the older walker’s long-standing medical condition, combined with the pair’s exhaustion, persuaded them to put in a 999 call to mountain rescue.
Teams were scrambled from Northumberland and from the Scottish side of the border.
A hastily-assembled team of five local BSARU members set off for the Auchope Hut and Cairn Hill from Sourhope, at the top of the Bowmont Valley, with team-mates arriving from further afield making their way onto the border ridge at Windy Gyle in case the walkers had headed in that direction.
A small contingent of unit members remained in the control centre at Sourhope to coordinate the rescue and handle communications.
The poor visibility ruled out any helicopter deployment, resulting in an energetic march across sodden ground and steep snow.
Shortly before midnight, the clag thinned sufficiently for a Sea King helicopter from RAF Boulmer to ferry a couple of Northumberland team members and a specialist search dog up to Cairn Hill.
The walkers were eventually located about 500m from the summit and evacuated by the RAF crew and helicopter.
The BSARU volunteers who had made it onto the hill were withdrawn and reassembled eventually at Sourhope, from where the 19 team members who’d responded to the call-out then wended their way back home for a few snatched hours of sleep before Wednesday breakfast and a return to their normal daily lives.