No sign by the cycleway announces your arrival into Scotland; only the presence of coach parties, swarming around the old blacksmith's shop, indicates you have crossed from England to a country composed of lowland and uplands, highlands and islands.The cartographer in modern Britain is largely constrained to adding double stripes of blue, signifying new motorways, largely through areas of outstanding natural beauty So the Sustrans maps are true works of art. Your passage to Scotland begins irritatingly slowly, since you are not actually allowed to cycle for the first half-mile - against the traffic along a one-way street. Indeed both kinds of poem - the real geographical, like the fine "Ancestors and Refugees", and the pseudo-anthropological such as "The Factotum" - are best when they have a clear and serious application. The poems are elegantly formed and verbally adroit but seem to confirm Allen as a poet of considerable technical skills who hasn't quite decided what his main subject is, despite impressive successes in several styles. Since the dramatic impact last year of Atlantis (Cape, pounds 7.00), his first book published in England, there has been little doubt about Mark Doty's central concerns.

You develop an intense fondness for the old A9, a meandering lane now largely abandoned to the weeds and the cyclists, and refreshingly clear of decomposing wildlife.The Sustrans trail begins safely enough, too, on a pedestrian precinct outside the old town hall in Carlisle. If you wondered what happened to old A-roads when they were rendered obsolete by expressways, the Sustrans route has the answers. And mostly, the plan succeeds in keeping you on byways, not highways. Yet it is part of the official slow road through Scotland, 402 miles from the border to Inverness. Fortunately, the guide to the Carlisle to Inverness cycle route assures you that these seven deadly miles comprise the worst stretch of the entire ride. The transport charity Sustrans, which has developed the route as part of the National Cycle Network, endeavours to keep cyclists separate from cars for the mutual benefit of both parties. The gutter into which you are forced to steer is littered every 20 yards or so by a corpse of some creature even lower along the evolutionary scale than a cyclist.

Drumochter Pass is one of the highest and most barren passes in Scotland. These days, it carries a high-speed section of the A9 between Blair Atholl and Aviemore. A yard to your right, 40-ton trucks are hurtling past at 10 times your velocity. The explanation of what they share is clear: as elegists, they both (like Yeats) find the taste of life sharpened by transience. But what they have in common even more fundamentally is that they are two of the best poets of our time..

Six days on the road, and 330 miles north of Carlisle, you begin to despise the Highlands and start yearning for the wide open flatlands of Norfolk. You have been pedalling uphill forever; well, for a good hour or so, struggling to maintain a steady seven mph against a wild west wind. The gale is whistling straight from Nova Scotia to the ancient granite mountains, riven by glaciers and tarred by 1980s roadbuilders. Brown wears the sea as clothing, as Doty wears the city; both use beached and wrecked boats as figures of life-in-death.