Just as Brown was once the new Blair and, fashionwise, brown is again the new black, so food also follows trends. The lazy Susan of table trends is ever-spinning - in 1989 nouvelle cuisine seemed for ever and superfoods unthinkable. The fate of food is as fickle as our appetites and against such forces no staple is safe. So prepare to drop your chopsticks: ceviche is the new sushi.

The raw truth is, we've now eaten just about all the sushi we can. There's a YO! Sushi on every corner and it's no longer novel. The restaurant chain Gaucho started with just one ceviche dish on the menu a couple of years ago. “Now we serve six different kinds and we are adding more,” says Ryan Hattingh, Gaucho's operations manager. “Our customers can't get enough of it.”

This spicy, seemingly raw Latin American fish dish was once served only in a few small Spanish restaurants in London. Now it's popping up on menus across the country. It can be found at the Blue Parrot Cantina, Edinburgh, and Britain's first dedicated ceviche bar just opened at The Club Bar & Dining, Soho - Raymond Blanc is a regular. “Thanks to sushi we're no longer squeamish about fish,” says Rasheed Shahin, its chef. “Ceviche is basically Latin American sushi.” Without the rice.

Like sushi, ceviche is low fat and high protein. It's even healthier because it's served with a crunchy salad - no stodgy carbs. It also packs more bite with its characteristic chilli and lime flavour. A ceviche craze swept America and it was served in star restaurants such as Balthazar and the 21 Club. Here, Nobu led the way with celebrity fans including Naomi Campbell and Jude Law. Ceviche (pronounced say-veech-eh), is perfect for people who can't cook because there is no actual cooking. Don't panic, though, it's not raw and flapping on your plate. “It's cured in citrus juices,” says Hattingh. “Peruvian fishermen needed to find a way to stave off hunger so that they could stay at sea longer. Obviously they had no fire to cook with, so they cured with lime.”

Citric acid denatures proteins in the flesh - and it's more delicious than it sounds. Others claim that cerviche is Ecuadorian or Mexican in origin. There are endless regional variations.

Gaucho offers five ceviche, ranging from the basic Ecuadorian (tiger prawns in a roasted tomato and lime sauce) to the more advanced fire & ice (lobster and shrimp, coconut and lime with red onion, jalapeño and coriander). “The key flavours are salt, lime and chilli,” says Hattingh. “It tastes hot but it's always served cold, usually with something crunchy such as lettuce or daikon.”

Rasheed Shahin says: “It's light and refreshing but has bite. It's more spirited than sushi and perfect for summer.” Shahin shows me how it's done: “The best fish for ceviche are meaty ones such as tuna or swordfish. If you're staying British, use bream or bass. Flaky fish, such as cod, won't work because the texture isn't right and oily fish, such as mackerel, don't absorb the citrus. Shellfish works really well - prawns, scallops and langoustines are perfect.”

Whatever you use, make sure it has not been previously frozen. “It's not just about flavour,” cautions Tim Croft, director of the fish suppliers Island Seafare. “A two-day-old fish is fine for frying, but not for ceviche because the flesh is tougher so the citrus won't get in, which means it'll be dangerously raw.”

If you're lucky enough to have a fishmonger, ask for day-fresh fish. Croft and his fish come from the Isle of Man, where every boat is out at dawn and back by dusk. From ship to shore to door in 24 hours. “Buy your fish whole,” Croft advises. “The gills are the first bit to go rancid, so lift and sniff. The flesh should have some redness, the eyes should gleam and the scales feel slightly slimy. If it smells fishy, it's off.”

We start with prawn ceviche. The prawns are shelled, scored with a sharp knife then blanched in boiling water for 15 seconds before being plunged into ice water. “This firms them up,” Shahin explains. They are then marinated for 30 seconds in the juice of four limes, two lemons and one orange. They're done when the colour changes from grey to pink. Add diced red onions and coriander leaves and arrange over shredded lettuce in a chilli and tomato sauce. Serve in a martini glass; it's basically posh prawn cocktail.

Next up is squid. This made me nervous. So often squid is more rubbery than the lips of Leslie Ash. But curing, rather than cooking, keeps it soft. Cut into rings and keep the tentacles whole. You don't need to press hard with the knife. “Squid is firmer, so marinate for at least six minutes,” Shahin advises. Customise your sauce with wasabi paste, roasted red peppers or sweet chilies. Artfully arrange on a baby gem lettuce leaf with a slice of freshly fried chorizo and half a boiled quail's egg. It looks totally cheffy.

Ceviche is more about preparation than cooking - slicing and dicing and lots of squeezing. Without a sous chef it's laborious. “You can't use juice from a carton because it lacks the acidity,” says Shahin, sensing a lazy cook. “Don't leave the fish in too long and eat it within 20 minutes as it won't keep.” There are no cheats. The only kit you need is a very sharp filleting knife, such as a Global or Sabatier, and a steady hand.

Ceviche is low-to-no-fat and couldn't be simpler to prepare or more impressive to present. It's far less fiddly than sushi. I am about to pour the marinade away when Shahin produces a bottle of vodka: “It makes the best hangover cure.” Now that's a superfood.

Sea Bream and Squid

FishWorks

Mitch Tonks, a former Tatler restaurateur of the year, is becoming the king of fish with his chain. Each restaurant is also a fishmonger’s. His fish come fresh from the morning auction at Brixham port in Devon. You can also order online. Availability depends on catch. “Throughout the spring black bream is caught on the South Coast. Bream is at the very top of my wish list; if you see one, change your recipe plans and buy it,” says Tonks. “If the flesh is at all pink, it’s not fresh: it should be pure white.”

Squid (cleaned): 400g, £8; delivery, £6.99. fishworks.co.uk; 0800 0523717

Scallops and langoustines

Isle of Skye Smokehouse

Harrods, Skibo Castle and the Royal Scotsman all use the Smokehouse. Its wild king scallops are caught by divers, so there is no dredging. This preserves both flavour and the environment. The langoustines are creel-caught off the Skye coast. Their meat takes ceviche flavours perfectly, and as they are already cooked, there is no need to blanch them.

Ten scallops (shelled and prepared) £15; langoustines £27.95 a kilo (unshelled); delivery, £8.95. skye-seafood.co.uk; 0800 7813687

Sea urchins

Orkney Rose

“Urchin roe makes delicious ceviche,” says Rose Grimond, the owner of this fish stall in Borough Market, South London. “Orkney urchins are smaller and less spiny. Cut open and scoop out the couscous-like roe.”

Live urchins £4 each (Friday and Saturday only). orkneyrose.com; 0560 1155643

The Club Bar & Dining

www.theclubbaranddining.co.uk

020-7734 1002

Gaucho www.gauchorestaurants.co.uk

Island seafare suppliers

www.islandseafare.co.uk

01624 834494

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