For Mustique, bring linen that is quiet, natural and made to last a week of salt, wind and long evenings: shirts and sets in a fibre whose origin is certified, cut loosely enough for the trade-wind heat. Pieter Petros dresses that week in certified Belgian linen, handmade in the Dubai atelier and in Belgium, with seashell buttons on most shirts.

Mustique has always been a place where people dress for each other rather than for an audience. The island, about 1,400 acres in the Grenadines, was bought in 1958 by Colin Tennant, later Lord Glenconner, who gave Princess Margaret a plot of land on which her villa, Les Jolies Eaux, was built. The stage designer Oliver Messel shaped its early houses and restored an eighteenth-century cotton warehouse as the Cotton House, still the island's hotel. Today Mustique is run by the Mustique Company, owned by its homeowners, and around a hundred private villas share its hills and bays. There are no crowds, and guests move between beaches in open-sided island vehicles known as mules.

That intimacy makes the choice of linen matter, and three things separate one shirt from another. The first is the flax: grown in the sea-damp fields of Flanders and northern France, its long fibres make a cloth that falls and moves with the trade wind instead of filling like a sail. The second is evidence. The Belgian Linen® mark is a private certification that follows the flax all the way to the woven cloth, and the Belgian linen certificate is the simplest way to tell real origin from a label. Third, the hand: garments made by people rather than lines, with buttons of seashell, or walnut on the Monte-Carlo Male shirt and the linen trousers, so that every piece is biodegradable by design.

The season shapes the wardrobe. Mustique's high season runs from mid-December to April, the dry months, when the north-east trade winds are steady, the afternoons sit around 28 to 30°C and the evenings are warm enough for short sleeves. Christmas and New Year are the busiest weeks of the year on the island. From June to November is the wet season and the Atlantic hurricane season, and the island is far quieter.

The day begins at the water. Macaroni Beach, on the Atlantic-facing east coast, is the island's long sweep of white sand, with thatched shelters and rolling surf; the bays of the sheltered west coast are calmer. In the sea and on the beach, a man wears PP swim shorts in Sapphire Blue or Vanille, cut from Belgian linen for the sea itself; the linen shorts wait on dry land. For the walk back to the villa, the Laos Short Sleeve Linen Shirt in White goes on over dry swim shorts. For her, the Linen Ladies Set in Coral Orange over a swimsuit, or the PP linen blouse in Lemon, worn open.

Lunch is long and usually taken at a villa. This is the hour of the Bliss Linen Shirt in Vanille, in certified Belgian linen, with PP linen shorts in Beige from the men's linen collection, and of the Amelia linen dress shirt in Oyster, with its walnut buttons, a dress in itself from lunch to sunset.

Wednesday belongs to Basil's Bar. Built on stilts over the water of Britannia Bay, it has been the island's meeting place for decades, and its Wednesday night jump-up, with live music and dancing on the deck, brings together villa owners, guests and islanders. Colour suits it. The Vibes Linen Shirt in Dubarry, in Belgian linen, its shorter, easy cut made for warm nights, with PP linen shorts in White; for her, the Amelia linen dress shirt in Hibiscus from the women's linen collection, which holds its depth under the lanterns.

The Cotton House is the island's more composed evening, with drinks on the veranda and dinner in gardens laid out around Messel's restored warehouse. Long trousers suit it for men: the Monte-Carlo Male in Vanille with PP Casual Linen Trousers in Sapphire Blue, and soft shoes rather than sandals. For her, the Amelia in Violet or Dubarry, two of the deepest colours in the collection.

A week on the island needs less than most travellers pack: swim shorts for the sea, a short-sleeved shirt for the day, a long-sleeved one for the evening, and one pair of linen trousers for the Cotton House. For her, the Linen Ladies Set by day and an Amelia linen dress shirt for each of the two evenings that matter. Everything can be ordered online and delivered to the villa ahead of arrival; in the Caribbean it is also presented at the Four Seasons Resort and Residences Puerto Rico. The wider island chain is covered in what to wear in St Vincent and the Grenadines, and the island's own rhythm in what to wear in Mustique.

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