The only swim I enjoyed was from a river beach, where families picnic beneath benignly sprawling rainforest. Dominica has nothing to do with palm-fringed golden sands (of the kind you might find in, say, the Dom Rep). It is instead a heroic crumple of stone that erupted from a fragile patch of the Earth’s crust. Today it seems frozen in mid-ascent, a jumble of rifts and peaks aiming for the grey Caribbean sky.Grey is not a colour that the travel industry promotes, particularly in the context of skies. But on Dominica it is a regular reality – a consequence of the collision between Atlantic air, heavy with moisture, and the highest mountains in the eastern Caribbean.Yet you will search in vain for evidence of gloom. The colours on Dominica are as intense as the most frantic afternoon downpour.

The furious rainfall – four times as heavy as in Britain – conspires with the rich, red soil to invent startling tones of yellow, garnished with abrupt flashes of scarlet. All this takes place against a background that explores every possible shade of green.Echoes of this anarchic colour scheme appear on every street in the capital, Roseau. The city – if that is not too bold a term to use for somewhere so motley – is rambling towards dilapidation. So the pinks and blues applied randomly to spare surfaces in Roseau are washed to a pale pastel.Dominica’s national institutions are crammed into awkward new concrete blocks and elegant old villas. To pick up a copy of the only good map of the island, for example, you must seek out the Department of Lands and Surveys. This ministry resides in a freshly painted clapperboard office that sprouts from a field on the fringe of Roseau. While you wait for your change, an official explains that this was originally part of the Rose’s estate.Rose’s grew on the lavish lime plantations that clung to the terraced foothills.

In the days when Dominica was one of the British Empire’s more irrelevant appendages, its prime function was to supply lime juice for the Navy. Eventually, better nutrition and artificial substitutes meant that the industry was eradicated as surely as scurvy. So limes went the way of vanilla, another one-crop wonder.For reassurance that the island can coax a living from the rumpled terrain, follow the citizens to the Saturday morning market in Roseau. Barrows are heaped high with fruits of little labour: bananas and coconuts, passion fruit and paw-paw, even the odd recalcitrant lime.The energetic faces of the traders and shoppers testify to the extravagant ethnic mix of the Dominicans. If you wondered how the Caribbean got its name, the answer is in the bright eyes and sharp features of the people of Carib descent. When Europeans overran the region and began to exploit it, the Caribs retreated to Dominica.