Here at Thetford there is a similar sign each side of the footbridge where, I believe, there once was a foot crossing.
If anyone can remind us when the crossing was taken out of use we can work out how long these signs have been in place and possible how many times the black apostrophes have been lovingly repainted in the wrong place...
UPDATE: This from Sinoda...
I believe the Thetford foot crossing was removed in about 1987/88.
About 3 years ago, a Sunday rail replacement coach driver, having been guided by his Sat-Nav, was found looking for the road level crossing.
Although on the same site, this had closed in the early years of the last century!