The Platinum Run.

The `Straight Line Mission` was first devised by the Youtuber Tom Davies, who completed his first successful `Mission ` across Wales in  February 2023 . The idea was to walk across a country from one side to the other in a completely straight line. In the UK this means crossing  private land on almost every step of the way. In order to make the project practical the straight line from the English border to the coast of Wales needed to be plotted extremely carefully to avoid buildings and other hazards.  This line was loaded onto a GPS and followed as exactly as possible. The prime interest and jeopardy of the videos was the need to avoid coming into contact with the property owners and farmers along the route. Open water was crossed on an inflatable canoe.  Deviation from the exact line was scored with the least deviation 25 meters designated a Platinum run and for deviations of 50 meters and  75 meters scored as Gold and Bronze runs respectively. This scoring was derived from a mathematical formula known as the Burdell score. The total distance of the Wales crossing was 42.1 miles.  http://www.youtube.com/@GeoWizard

For the England's Longest Path at 369 miles if one was to use a formula in which the Platinum, Gold and Bronze runs  are  defined as a percentage deviation from the total length of the path compared to the Wales run, the Platinum Run would be anything which deviates less than 250 meters from the straight line. For a line of the distance of 369 miles this would still make for a very difficult Straight Line Mission.  The England's Longest Path line is not tweakable and therefore some allowance has to be made for that fact. It may be possible to complete a `Mission` with ingenuity, but across this length of England there are more motorways and railways to cross making a mission of this type improbable and dangerous and illegal in the criminal sense. Trespass on private property is a civil offence. Trespass on motorways as a pedestrian, or on the Railways are criminal offences.

Some sums. Tom's crossing of Wales: 42.1 miles, which is  67,753.38 meters /25  = 2,710.1352 meters
England (longest)  : 369 miles is 593,847.9 meters /25 = 23,753.916  meters a ratio of 1 to  8.76 (not quite 10 times further). 

Therefore for the strictest Platinum run I am going to suggest 250 meters as a practical deviation for Platinum, with gold at 500 meters and bronze at 750 meters. This allows for navigation around buildings and city streets. The bad news is that even with these relaxed rules a Platinum run is impossible because of motorways. I did think you might find a way of flying across these obstructions using a trebuchet and base jumper's parachute, but really the best solution  is to exempt these from the rules. After all, peoples lives would be at risk. Therefore the rule at motorways is you walk to the point where a motorway intersects the line, You make your way to the nearest pedestrian crossing and then return to the point where the line intersects the other side of the motorway. Job Done!
It seems that every railway can be crossed within 250 meters of the line but there are a great number of river crossings (13) and two reservoirs.

Legal Platinum

England's Longest Path aims to be legal and in order to keep it that way I am going to suggest a  Legal Platinum run is one that deviates less than 1.5 miles from the straight line. If you have read this website this far you will know that  the largest deviation is at Akle Bridge in Norfolk at 1.9 miles. For a Platinum run that is still legal, the river Bure which it crosses, could be crossed legally by watercraft or swimming, much closer to the line. With various other modifications to the original route I have plotted what I call the Legal Platinum Run with a maximum deviation of 1.32 miles just outside Launceston.  This should be combined with the original England's Longest Path GPX files from which it deviates. Where it uses EL tracks this track becomes a straight line until the next deviation.