Map

It's interesting to come to a motorway bridge you've been over a hundred times without realising there's a canal underneath.

This is the M40, just southeast of junction 16, when you're beginning to think about which lane you're in for the M42 (or relaxing after leaving the M42 behind and beginning to think about a Starbucks at Warwick services). It's just at the join of four pages in our road map, which doesn't make much of canals anyway, so that's perhaps another reason why we've never noticed it before.

Nicholson's raison d'etre, on the other hand, is the canals, to the extent that the guide has a blown-up bubble for a complex junction. We're leaving the Lapworth flight for another day, so decided to move over to the Grand Union for the night, tie up at Kingswood, and walk across to a nearby National Trust property tomorrow. Following the map, we turned very sharp right at the junction – you can hardly see the cut until you're on top of it. Then we expected to find the other branch to the Stratford through lock 20 joining us from the left.

Didn't see any sign of it immediately, but put that down to Nicholson's occasionally relaxed approach to scale. So, when we did reach a junction, we turned right, expecting to find the main junction with the Grand Union a bit further on. After two hundred yards we realised we were already on the big one, and heading rapidly for Warwick. Not at all where we wanted to be going.

A quick check of my reliable Nicholson's said there wasn't a winding hole for several miles, so there was nothing for it but to reverse back round this gentle bend, with two moored boats waiting for a collision, and the canal so shallow it would insist on pointing Erin Mae in the wrong direction. We eventually made it without mishap, but at the expense of I don't know how much extra diesel!

Ah well! I thought of walking back to find the invisible junction, since we want to go up there on Sunday anyway. But it's raining again. However, there's some wonderful food in the pot, a good enough TV signal to follow Andy Murray's progress or lack of it this evening, enough juice in the batteries to allow us to do so, and a good enough Three signal for this blog post. And tomorrow we are promised sunshine for our walk.

Hope we don't get lost.