On St George's Day, Paul Heslop sets forth along a route which shows the local countryside at its very best.

ST GEORGE'S Day, and England couldn't have been better presented. I had come to the shore of Tring Reservoir, near Marsworth, "a village for narrowboat lovers", where the waters of the nature reserve shimmered in the warm, spring sunshine, and the flag of St George fluttered lazily from the tower of All Saints' Church in the middle distance.

Marsworth stands near the junction of the Grand Union Canal and, dramatically, the reservoirs, or nature reserves. The lakes are man-made, constructed between 1802 and 1839 on high ground as feeders for the canal, and now, happily, a recreational area "popular with walkers, fishermen, picnickers and wildlife enthusiasts". The reservoirs form one of the most important wetland sites in the country.

I was bound for Bulbourne, via the towpath. Popular this area may be, but there were few people about on such a grand morning: one or two fishing, a cyclist, grandparents with tiny tots, all at ease in this lovely place. Everyone was smiling, as everyone would be on such a morn.

At Bulbourne, the Grand Junction Arms is a reminder of the canal's original name. As long ago as 1793, royal assent was granted for its construction, linking the Thames with the Midlands, the first planned route northward since Roman times. Barges carried everything, including coal, manure, timber and even soldiers in days before metalled roads and railways. Today's narrowboats carry holidaymakers, although I saw none today.

I retraced my steps, joining the Wendover Arm of the Grand Union. Here were grasses, nettles, a mishmash of unidentified (at least to me) wild plants and shrubs lining the canal towpath, while on the other side the spindly branches of high hedgerows trailed in the water. Unseen birds sang merrily, and even moreso in the woods further on. Spring is a happy time for birds.

The path led to the other side of the reservoir, where information about the nature reserve and its habitat is provided: many trees in the woods I had walked through fell victim to Dutch elm disease in the 1970s, but other trees have taken their place; the pipistrelle bat, Britain's smallest, weighing in at 4 grams and only 4cm long, devours 3,000 insects a night at the water's edge; a hide is situated nearby, an ideal place from which to spot kingfishers.

I moved on, the extensive Vale of Aylesbury coming into view, to Wilstone Reservoir, another nature reserve where more birds, including swans, seek, almost demand, titbits from passing hikers, especially those who take advantage of a convenient bench by the water's edge. The bench is dedicated to a woman who died in 2000, by "all those who loved her". It could not be better sited.

Wilstone was a picture, the little village pump surrounded by pansies, and the war memorial proudly sporting a rosary of poppies. Everything belonged to the day. The Half Moon pub was the venue, in 1751, of the inquest into the deaths of Ruth and John Osborn who were accused of being witches and murdered by ducking in a pond (now gone) by Thomas Colley and a mad crowd. Colley was himself later executed and his body hung in chains at the scene as a warning to those who would murder so-called witches.

Another half-mile led to the Aylesbury Arm of the canal, with its arched bridges and tree-lined banks. This mile-long section to Marsworth Junction gets my vote for the best stretch of all, especially on such a day, and even more especially when, further on, Marsworth church comes into view. It's worth going all the way to the junction with the main canal, not least to reflect that all around you is the product of human hands so many years ago.

Marsworth gets its name from the Old English for "Maessa's enclosure". There are pretty cottages here, and the superb church, All Saints', dates back to the 14th century. It's in a light-grey stone and, from afar, always seems to be in view, as though inviting one to visit, as I did. It is a good place to linger, before returning to Startops End, where today the Anglers' Retreat sported an enormous flag of St George.

Quite right, too.

Approximate distance: 8 miles

Start and Finish: Car park, Startops End, near Marsworth (all-day parking costs £1)

Route

Startops End, Tring Reservoirs (nature reserves), Grand Union Canal, Bulbourne, Wendover Arm of the Grand Union, Wilstone Reservoir, Wilstone, Aylesbury Arm of the Grand Union, Marsworth

Abbreviations

l.=left; r.=right; n. s. e. w.=north, south, east, west; br.=bridge; r.o.w.=right of way; PH=public house; m.=mile; s/post=signpost; f/post=fingerpost; b/way=bridleway; ch.=church; f/p = footpath; r/way=railway; cont.=continue; FM=farm

Routefinder

Visit reservoir/nature reserve, follow canal to Bulbourne. Retrace steps to Wendover Arm, which follow quarter mile, to r.o.w. through woods to reservoir. Retrace steps into wood and fork r. to road. Turn l. towards Tring, take r.o.w., Grand Union Canal Walk to Wilstone Reservoir. Take r.o.w. to rd and Wilstone, then f/p alongside play area to canal, Aylesbury Arm. Do not cross br. Turn r. follow to Marsworth Junction. Retrace steps to Bridge No 1, to Marsworth & ch. Take Vicarage Rd to main rd, turn r. to Startops End.

Pubs

Startops End: Anglers' Retreat, White Lion

Bulbourne: Grand Junction Hotel

Wilstone: Half Moon

Note

A book identifying birds, and food for them, would be useful on this walk