POSH potatoes, which top chefs tend to drool over, are put under the microscope in the latest Which? Gardening.

These gourmet spuds are usually smaller than conventional varieties, most have a waxy texture, a supreme flavour and are terrific served cold in summer salads.

So which are best? The Which? tasters trialled 19 varieties, including newies, salad sorts and some reintroduced heritage and novelty names.

The team's Best Buy was Charlotte, a clear winner in the taste test, the second-heaviest cropper, producing 57lb from 20 tubers, and widely stocked. Mimi, said to be good for containers, has an earthy flavour but yields were not high. Congo, dating from the 1890s, is an ugly bug with strange, inky-purple flesh but deceptively tasty and was labelled as an "interesting novelty.

Highland Burgundy Red makes striking pink mash, crops heavily and is great roasted or fried. Mayan Gold, with yellow flesh, made the perfect baked spud and is "worth trying", as was Mr Little's Yetholm Gypsy which was saved from extinction when down to the very last tuber and was subsequently micro-propagated. Salad Blue proved the top cropper of the contenders — 68lb from the 20 tubers — though its mauvy-purple colour could be an appetite killer. And Pink Fir Apple cross Anya is knobbly like its parent and made tasty mash, but the panel were downbeat about its flavour and reckon it is better harvested early as a salad potato.

Buy at Thompson & Morgan (0844 5731818) for Mimi and Congo, Edwin Tucker (01364 652233) for Highland Burgundy Red and Salad Blue, Mr Fothergills (0845 3710518) for Mayan Gold, Alan Romans (01337 831066) for Mr Little and practically anywhere for Charlotte and Anya.