Kenza, 10 Devonshire Square, London EC2, 020 7929 5533

"Home-style Moroccan and Lebanese cooking" – does the phrase make your heart sink? Does your head fill with tagines of boiled meat on couscous, pigeon pie in impenetrable pastry, overcooked root vegetables, houmous and aubergines and no subtlety? Me too. Whether it was Fakhreldine in Piccadilly, or Momo off Regent Street that first established my ironclad prejudices, I've never nursed any expectations that dealers in Middle Eastern cuisine will stray from the utterly predictable. But I took my friend Penny to a new place, Kenza, sister restaurant to Pasha in Kensington, prepared to be converted.

It's located in trendy Devonshire Square near Liverpool Street Station, a bricky enclave of bars and eateries where exhausted City types can unwind and go for whole quarter-hours without thinking about Northern Rock. You enter down a graceful spiral staircase spread with rose petals, and find yourself in a little dream of North African luxury – ornate orange walls, cushions, candles, rugs, recessed lights and complex tracery – inhabited by a morose handful of young City people (black suits and skirts, white shirts and chemises) like scholars from an unusually strict academy.

A large, attentive maître d' waved cocktail menus and, when we asked him to choose for us, he selected two of the house's most expensive. My Junan (champagne, Bombay Sapphire gin, fresh pear marinated in cinnamon) was deliciously fruity and frisky, while Penny's Dhia (Hendrick's gin, with cucumber, ginger and lemongrass) had a nice Pimm's-y kick, but at £10 and £9 respectively, they should be damned exceptional.

The belly dancers appeared, grinding and wiggling their way around the tables for five minutes. One was from Brazil, all passion and enthusiasm, one appeared to have learned her skill by correspondence course, and a third was an amazingly statuesque performer whose surging, nuclear-warhead breasts and rhythmically undulating thighs seemed to move independently of each other. What a charmingly louche cellar, we decided. "If this were in Soho," said Penny, "It would be packed out." She indicated the monochrome City clientele. "They say that youth is wasted on the young. Well this place is wasted on pallid bankers."

Given its dedication to hedonism, we were sure this charming pasha's crash-pad would offer something different – some authentic, lovingly cooked nouvelle cuisine Maroc...The menu offered a prix fixe – two small dishes from a list of mezza plus a main course, for a hefty £28. Plates of crudités and pitta bread were plonked down, along with jalapenos, which seemed to have come from a jar, and beetroot that had been pickled until it resembled sections of a diseased lung.

The mezza, when they arrived, fell short of expectations. The exotic-sounding "Deep fried pumpkin and cracked wheat parcels filled with onions, walnuts and pomegranate molasses" were unmasked as small, tasteless spring rolls, the "Pan-fried, home-made, Lebanese lamb and cumin sausages" were OK, but sat unhappily in an off-putting soup of lime, mint and cumin. "Baby tiger prawns with crispy aubergines and spicy sauce" were nobbled by a truly terrible tomato salsa. Only the char-grilled marinated quail with pomegranate was a success, its tiny legs succulent and tangy. All the "deep fried" and " pastry-filled-with" selections seemed hopelessly under-flavoured; I could be wrong, but I can imagine them being bought by the dozen from a Tasty Nibbles wholesaler in Bethnal Green.

After a lengthy interlude in which a handsome but bossy sommelier tried to persuade me to spend £28 on a Moroccan red wine called Riad Jamil (I tried it – nice fresh bouquet, no character, no finish), we hit the main courses. My S'csou Darna (lamb shoulder with char-grilled Merguez sausage, chicken skewer and vegetables) was authentic home-cooking all right – over-cooked until on the fibrous side of tender, the merguez juicy but the chicken shockingly dry and the vegetables soggy. OK, you might find something like this dished up in a café on the edge of the Djemma el-Fnaa in the heart of Marrakesh, but I expected something a little more sophisticated for the inflated price.

Penny's tagine of chicken cooked in preserved lemon, garlic and turmeric sauce was "nice and lemony, but it's hardly what you'd find served up at the Topkapi Palace of Suleiman the Magnificent, is it?" That was the trouble with Kenza – lots of thought has gone into designing a corner of Mahgrebi exoticism in Nowheresville, London EC2, but the food just isn't special enough. The afters menu offered baklava (Syrian, not Greek) and halva ice-cream with a hazelnutty brown sauce, and a milk pudding called moulalabia, flavoured with rosewater and pomegranate syrup, which was basically junket – flavoured like the perfume counter at Debenhams.

The belly dancers, whose presence allows the management to rack up the prices to stratospheric levels, have gone home to their virgin divans by 9.30, and the music turns, not very Moroccanly, to Euro-Club Mix drum'*'bass. The City guys'*'gals chat earnestly about portfolio management. Our attentive waiter, a dead ringer for Zinedine Zidane, looks crestfallen that we didn't finish everything we ordered. It's hard to identify the precise level of disappointment that you experience at Kenza. Put it like this. You enter the place thinking about Scheherazade and the 1001 Nights. You leave feeling you've been to a provincial performance (with interval snacks) of Kismet.

Kenza, 10 Devonshire Square London EC2 (020-7929 5533)

Food twostar
Ambience threestar
Service threestar

£132 for two with drinks