The deputy ambassador asked me out to dinner. I normally get the temporary media-liaison girl from the British Council, but as I was travelling with Jeremy off the telly, I got upgraded. “There’s a place we use, nothing special, obviously not what you’re used to,” he said, with that air of self-deprecation that miraculously increases the stature. It’s a trick diplomats are taught in the witchcraft school of the Foreign Office.

What was odd, not to say bizarre, about this was that we were in Baghdad. We sat outside in the balmy evening, around tables with gingham cloths under palm trees, in a courtyard screened by a labyrinth of blast walls and partitions of sandbags. At the other tables were men in smart tropical casual having a late dinner, their assault rifles propped against their chairs and 9mm pistols beside their duty-free Marlboro Lights.

It was all out of bounds to American personnel, so it was the only place in Baghdad that seemed properly international. The waiters were jolly Iraqis. The food was meze, some rather good hummus and a mixed grill and chips that was on the cold, clammy side.

But that was all beside the point. Just to sit here for an hour and go through the ritual of hospitality was an act of faith, homesickness and bravado. Restaurants are the summit of civilisation. It took us 10,000 years to get to one. You have to have a lot of other things in place before you hire a head waiter: safe streets, a reliable supply of utilities and ingredients, clean water, customers with disposable income, freedom of association, peace and goodwill. None of which Iraq can stretch to at the moment.

So, sitting here, chewing the tepid fat while the American Black Hawks wop-wopped overhead like Tolkien’s dark riders, was doing something that was either foolish or important. It was rearranging the deckchairs on the Titanic — or a vote of confidence that you could, in fact, rebuild the Titanic at sea as it sank, starting with the chips.

I also ate at the American commissariat, Uday’s shag palace, now a huge canteen for soldiers; trestle tables of edgy, camouflaged men and women with that corpulent look of America’s underclass. Around the walls was a help-yourself cornucopia of American comestibles — gluts of burgers and hot dogs, flocks of fried chicken, sweet potatoes, pizzas, chops — all fatty, sweet and familiar, served on huge plates with supersize cartons of Day-Glo soda. I had never seen comfort eating of such concentrated, panoramic intensity. They were heads down, cramming their mouths with home. How you eat and what you eat are symbols of what and who you are — and this is never so potent as when a man is continuously scared, day after day, and a long way from his bedroom.

The Americans regarded us with suspicion and blank hostility. This wasn’t the texture and taste of our home. We were trespassing on the communion of their lunch, the remembrance of a thousand small-town diners, trailer-park kitchens and back-yard barbecues. The high altar of the canteen was the ice-cream counter. It was the real thing, served in a one-size bucket you could have drowned kittens in. The flavours revolved, new ones arriving every three weeks as the old ones were sent home. Tank crews would drive hundreds of miles to get a new taste of Stateside. Soldiers carried tubs back to Humvees and personnel carriers like holy relics; a mouthful of sweet unction to calm the churning shock and awe.

Someone dropped a tray. The crash echoed into the high dome and a thousand kids lurched for their weapons, ducked for the floor, eyes staring, teeth bared, choking on tutti-frutti.

Which brings us — or doesn’t bring us — to Roast, a new restaurant in Borough Market. The weekend market here has become a foodie Groucho Club for organophiles and artisan producers who see food as politics and social science before breakfast. I don’t mean that to be snide. They’re right. But sometimes their proselytising makes promises their sausages can’t rise to.

Roast is a nice, big, airy room. The menu is British: not the tarty “Brit with a twist” of Gary Rhodes, but the low-church, born-again Camelot of Fergus Henderson, whose restaurant St John must now be the most influential kitchen in the country. This is a marvellous and hopeful thing, but a lot of Henderson’s would-be acolytes are finding that the transparently simple menus and recipes are actually druidically difficult. The fewer the ingredients and the more straightforward the method, the fewer the places to hide dull ingredients and clumsy preparation. Roast is some way behind the curve of its aspiration to be the Lancelot of British grub.

I started with a duck salad that consisted of a fan of labial magret, a hunch of little gem and three boiled, bland mini carrots. It was a depressing bit of catering construction.

Next I had grilled ox heart. I haven’t eaten an ox heart since they forced abattoirs to slash their ventricles and, with one stab, murdered a transcendent British dish: roast stuffed heart. Grilled in slices, it has the texture of liver and the thin, sharp flavour of fillet, which was augmented with nice dabs of bone marrow. It was fine, but not really an improvement on calf’s liver, unless you are doing a Duke of Edinburgh award in offal. Puddings were the usual best-of-Brit treacle tart with anaemic, flabby pastry, and a sticky toffee pudding that was just badly made.

There were some good things: the pilchards and the Dublin Bay prawns were nice. Overall, though, Roast is lacking in confidence and generosity. For weekend lunch, it will have to compete with the stalls and new-age medieval pie men of the market, and there is still some way to go before it becomes an evening destination. If you want to cook British, you have got to be a bit more Falstaff in the kitchen. Roast just doesn’t have enough greed or gusto.

Lunch, Mon-Fri, noon-3pm, Sat and Sun, noon-4pm; dinner, Mon-Fri, 5.30pm-11pm, Sat, 6pm-11pm

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