The thought of the 75-year-old actor Brian Blessed on a narrowboat is one that should immediately bring a smile to your face. It certainly did for me. In my mind’s eye he sits there like a thespian Captain Haddock, roaring with ebullient laughter. And British Waterways, who have got Blessed on-board (so to speak) to publicise a new campaign to attract volunteers, are hoping that once you have stopped chuckling, you will be inspired to volunteer as a lock keeper.

As a child, Blessed explains, he spent many happy hours by the canals, “exploring on my bike and looking for wildlife”. Now he is keen that we all “do what we can to help protect them for our next generations”.

The canal network is being transferred to the charity sector, under the newly-formed Canal & River Trust. This means that there are now 61 locks in need of volunteers, everywhere from Bradford to Bath. In return for one day per week, you receive full training, a uniform, and the opportunity to become part of an ancient and colourful tradition. According to Ed Moss, the Trust’s national volunteering manager, the role of a lock keeper is “the most symbolic on the waterways”. It’s a perfect hobby, he says, for people who like working outdoors, meeting a wide range of people, and trying their hand at something different.

So, one glorious winter’s morning I head down to the City Road Lock in Islington, on the Regent’s Canal (which celebrates its 200th birthday this year). There I am met by two rugged lock keepers, Paul Crowhurst, a retired fireman, and Mark Loveday, an ex-Royal Marine (it’s the uniforms, Crowhurst explains).

There is also a handsome narrowboat bobbing in the waters, skippered by an old sea dog whom I initially mistake for Brian Blessed (why do all captains have beards?). Dog walkers bumble along the towpath. The only sign that we are in London is a dead pigeon in the canal. Continue reading on the Telegraph website