TrigpointingUK

Here's a random one, was just wondering if anyone knew which pillar in the UK was the furthest / toughest to get to. Have done a lot that were roadside or an hour or two walk but was just curious which required the most effort to get to?

TP6454 Thornton - short but hellish. Check out the reports. Probably some gorse infested ones in the north too.

In the highlands...

Creag Mhor - http://trigpointing.uk/trig/2561 and Ruadh Stac Mor - http://trigpointing.uk/trig/5761 are both contenders. Or maybe Beinn Bhrotain in the Cairngorms - http://trigpointing.uk/trig/1166

Depends what you mean by furthest, of course. I did put on a pevious post (Mon Feb 06, 2017) asking if the remotest in England & Wales is the Glendhu Hill pillar (TP3384) on the Northumberland/Cumbria border, close to Scotland. It's an 8km walk to get to. In a straight line the nearest public road-end, Dykecofts across the Scottish border, is nearly 7km away but impractical to reach the trig from. In practice, Glendhu Hill wasn't the worst of the Kielder/Cheviot remote trigs to get to as there were good forest tracks most of the way; The Grun (TP6387) took longer and was a gruelling trek.
Berrymoor Edge (TP1340) runs Glendhu Hill a close second if you don't count the Kielder Forest Drive (which closes over winter) as a public road. Taking a straight line from Berrymoor Edge you'd need to swim across the Catcleugh reservoir to reach the nearest road in less than 6.5km.
A clever person with the trig database, OS vector maps data, and a GIS programme could give a definite answer, but it wouldn't be easy!