The very lost tunnels of the Hereford and Gloucester Canal

Paul and Rebecca Whitewick take us to Oxenhall and Ashperton, the two abandoned tunnels on the Hereford and Gloucester Canal.

For more about this lost waterway, see the Herefordshire and Gloucestershire Canal Trust website.

The Holy Dipstick of Salisbury is now just for show

Salisbury Cathedral's foundations are so shallow that it effectively rests on a bed of gravel and water. If the water gets too low, it has to be topped up to keep the building up.

Which is why the cathedral, as well as attracting dubious Russian tourists, inspiring The Spire by William Golding and housing a bust of Richard Jefferies, has a dipstick.

This was used to measure the water level under the cathedral, so it could be topped up if necessary.

Paul Whitewick says a system of sluices was built to make this possible, but today the water is monitored automatically by the Environment Agency, so the Holy Dipstick of Salisbury is just for show.

But he couldn't discover where the water it taken from.

The two lost canal tunnels of Blisworth

Inspired by the research of Tony Marsh, Paul and Rebecca Whitewick travel to Northamptonshire and the Grand Union Canal to look for signs of two tunnel alignments at Blisworth that were begun and abandoned before the one we know today was completed.

They also find some remains of the railway that was used to ship goods over the hill before the tunnel opened.

There's more from Paul and Rebecca Whitewick about their railway and canal explorations on their website.

Is the Ridgeway really 5000 years old?

Paul Whitewick takes us from Ivinghoe Beacon in the Chilterns to Wiltshire. There we see Liddington Castle, which was sacred to Richard Jefferies, and then some of our sexiest prehistoric monuments, if Avebury and Silbury Hill will forgive me for calling them that.

How old is the Ridgeway? Is it really one path at all? Long walks are good for pondering such questions.