Slowly cooked and stored in its own fat, duck confit can be a tender, melty delight. Its fatty skin, when pan-seared to a bronze crisp, is the most irresistible casing for salty and succulent duck meat this side of Beijing.

But like most routinely reheated meats preserved duck is prone to dryness. This is especially problematic when the leg meat is skinned and shredded for the likes of duck confit tarts, spring rolls and tacos.

One surefire if unconventional way to dry out skinned and shredded duck confit meat would be to spread it out over the bottom of giant paella pan and let that pan heat over a direct fire in a covered market for hours. Le Marché du Quarter, a French foods vendor at London’s Borough Market, demos this new technique with the hacked duck confit meat its affable servers squeeze into ciabatta sandwiches. The bread is brushed with Savora, a French mustard with a flavour comparable to British Piccalilli, but sadly this application is of little practical benefit. No amount of additional mustard, duck fat, mayonnaise or other first-aid sandwich pommade could sufficiently moisturise the dry, throaty meat. Small wonder the sandwich is called “Le quack”.

You might think the author of three French cookery books who chooses to call himself young&foodish would know better. Yet there I was on Saturday, dutifully lined up with the other punters like ducks in a shooting gallery to pay £5 for sandwich meat I wouldn’t swallow again unless they shoved a tube down my throat and force-fed me in the manner of a foie gras-producing duck.

Le Marché du Quartier’s duck confit-in-a-paella-pan sandwich does make for great market theatre. Viewed from the rear of a long queue – make that a very long queue – the duck confit suggests an enticing alternative to salt beef or pork belly. As a London sandwich scout I had to make certain this wasn’t Borough Market’s next exceptional meat sandwich. I’m sure others on the queue felt they too could risk it for a fiver. Whoever orchestrated this spectacle of a generously stuffed sucker sandwich is one cunning quack.