I really don't understand the open hostility in this thread? There is absolutely no need for all the patronizing criticism! The guy has set himself a challenge and good luck to him!
I think everyone wishes him good luck.
The main problem here is that there are no 'wilds' of Britain that aren't owned by someone, and so by definition if this undertaking goes ahead it will involve taking from someone, unless by some incredible stroke of good fortune a 'sponsor' agrees for his/her land to be used as the individual sees fit for the duration.
Scenario for you:
Someone saves hard to afford a deerstalking or salmon fishing trip to (insert suitable name of remote and scenic location) and, whether the hunt/fishing is successful or not they return feeling suitably rewarded.
Someone else goes the week after and all hell breaks loose when it is discovered that a guy has established a semi-permanent camp on the estate and is poaching the salmon/deer as a staple food source, burning timber from the forests for warmth, foraging and otherwise helping himself from the estate's resources.
England (read Great Britain, including the various surrounding islands) is only a 'green and pleasant land' due to agriculture, farming and forestry where enormous investment and effort is made to keep it that way.
Large game herds are carefully managed to preserve healthy populations, and the 'quintessentially English' pheasant is an introduced, non-native and bred for sport bird that generates much needed return for those estates that run shoots.
Yes, it would be nice if there was land available for folks to use freely. The bottom line is this: there isn't. As such, use of any land has to be done with permission and (often) fees.
Spin it any way you like, but helping yourself to the land's resources is the same as shop lifting from Sainsbury's shelves. There are penalties for both activities.
I own some land in the UK and more in Canada and I am constantly on the lookout for takers who are there to help themselves.
How can this person achieve the goal without falling foul of the law ?
Anyone with an interest in the outdoors can relate to the concept of going off the grid. The realities though, present a series of problems and most of them involve breaking various laws.
If someone wants to buy a small holding and live how they choose on their own patch the reaction would be very different.
This person wants to live how they choose on someone else's land and off someone else's resources, which is where the problems begin.
I think you might be mistaking simple logistical issues for hostility.