Keu! Banh Mi Deli is Dalston's speciality

When I first arrive at Keu!, they've got an evangelical Christian radio station on in the background.

Is this what the hipsters of Shoreditch are listening to? If so, it seems to be working.

The speciality of this unlicensed sandwich bar is Vietnam's most successful culinary export after the spring roll: the banh mi, a baguette stuffed with barbecued mackerel or some form of pork, pickled daikon radish, coriander and mayonnaise.

But at 7pm, a full hour before closing, they're down to the last one. Countless chaps with interesting trousers are turned away, disappointed.

Next day at noon, Keu! is rammed again, even though it's surrounded by cheap, cool Indochinese eateries. Indeed, it's part of a mini-group that includes Cây Tre, opposite, and Viet Grill on Kingsland Road. But the gaping front windows, and black-wood-and-bare-brick interior are sleekly alluring. There are light fittings that look like they've just been knocked up by Thomas Edison hanging over the counter-style tables, and succulent bits of pork and duck on hooks behind the serving area. Shelves by the door offer bright displays of Sriracha hot sauce and Kewpie mayonnaise. The staff are cute and smiley. And for a quick solo lunch or fatboy breakfast, a substantial banh mi for £4.50 looks hard to beat.

The mackerel is the best - the crisp crust giving way to a juicy, aromatic, pungent filling. But the shredded lardo (bacon) in the Banh Mi Bi is overwhelmed by smoked ground rice and daikon pickle, while the combination of spiced pork, ham terrine and chicken liver pâté in the Keu Classic
gives that unmistakable "bit sicky" feeling.

Unctuous pork meatballs can be ordered in a roll, but I have them under-sauced on rice in a £5.50 lunchbox. Another 50p buys roast duck of almost treacly fattiness with good rice and steamed greens. Specials at £5 are different each day: Saigon beef stew with star anise and cinnamon boasts melting slow-cooked meat but thin gravy.

The "salad" of translucent rolls stuffed with shrimp, herbs and vermicelli is fresh and crunchy but needs the boost of soy or chilli.

Smoothies and juices are excellent despite being called things like Good Morning Vietnam (groan), while coffee is served in all its high street manifestations, or Hanoi-style, with syrup. Best to give the artichoke tea or pennywort drink a body swerve, though. This place has novelty and style and sells exotically unfamiliar condiments, all qualities prized in ECI. But Keu! apparently means "that's fantastic" in Vietnamese. Which is overstating the case a bit.

Keu! Banh Mi Deli
332 Old Street, EC1