Iain Miller has been at it again. Oh dear. Will someone lock him up for his own safety!

Miller, who has been pioneering new routes up the sea stacks of Donegal, Ireland, has ticked the last unclimbed stack in the An Port area.

Miller teamed up with visiting North Wales resident Adam Wainwright to climb Hidden Stack via an amenable 3 pitch VDiff.

The route description is as follows:

Grid Reference G556907.

Hidden Stack sits in the channel separating "Tormore Island" and "Cobblers Tower." Access is by a superb paddle from the storm beach as for "Cnoc na Mara." This route climbs the Southern Ridge, the first feature on the stack you see as you paddle up the channel towards it.

Pitch 1. 15m From the non tidal platform at the base of the South end, climb the up the left side of the South facing ridge to a large ledge.

Pitch 2. 15m Continue up the ridge to a lonely huge Basalt boulder.

Pitch 3. 12m Scramble along the summit ridge. Abseil descent down the seaward face from the Basalt boulder. The sea around "Hidden Stack" are very tetchy indeed and require due nautical care.

Iain Miller produced a brief guide to the sea stacks in the area back in May 2009 that UKC published here: The Sea Monsters of Donegal - A Brief Guide

• Iain has now sent an updated version of his guide: UPDATED: Donegal Sea Stacks 2010