Testi is not a crude novelty restaurant (the name actually means “water jug” in Turkish). Lamb’s testicles, however, are the signature dish at this Turkish ocakbaşı restaurant. Grilled in their spicy marinade, the taste falls somewhere between sweetbreads and kidneys, but far less uric. Unpredictably delicious. Testi’s Albanian-style chopped liver is also worth ordering.

A contender for coolest restaurant in north London, Black Axe Mangal operates from a tiny space on Highbury Corner. Chef Lee Tiernan’s cooking is almost as loud as the restaurant’s playlist: a hit parade of (mostly) ‘80s thrash metal. Lamb offal flatbread is unsurprisingly popular, served from the KISS-inscribed pizza oven — like a Turkish pide topped with hunks of lamb, mayonnaise and hot sauce. Elsewhere, sweet, savoury, tart, nutty and salty foie gras, prune and almond doughnuts are a triumph in innovation and excess.

Smoking Goat’s ‘Offal Mondays’ ended with the closure of the original Soho restaurant, though some exciting offal dishes have been transported to the Shoreditch site. Soya-braised chicken features a combination of Chinese and Thai flavours, with a secret weapon in the guise of gelatinous feet added to the fragrant cooking liquor. Moreish chicken heart skewers are very fairly priced at £1 each.

St. John has been revolutionising nose-to-tail dining since 1994. A stone’s throw from Smithfield Market, the Michelin-starred restaurant has an unassuming, canteen-like dining room and serves a daily changing menu of charming (often overlooked) British classics. Menu highlights might include pig’s trotter and potato pie made with buttery suet pastry, or bone marrow salad comprising four tunnels of roasted veal bone with parsley, shallot and caper salad; served with toast. One of London’s most iconic dishes and an absolute must-try.

Restaurateur Geoff Leong’s most celebrated Chinatown site: Leong’s Legend serves an extensive menu with plenty of nods to Taiwanese cooking. Various seafood dishes are available, while the restaurant’s xiao long bao are some of London’s best. A trough of hotpot, on the other hand, is a true celebration of the pig: a melange of pork belly, slivers of blood cake and chopped intestines bathe in unctuous, fat-enriched broth that’s bolstered by fistfuls of Sichuan peppercorns.

There’s plenty to dote over at Barrafina, but the milk fed lamb’s brains are the jewel in the menu’s crown. Breaded, deep fried and finished with pine nut tapenade, the brains take diners on an adventure in complementary textures. Modelled on Cal Pep in Barcelona, Sam and Eddie Hart opened the tapas restaurant in 2007, and have since opened two further branches. Pig’s ear carpaccio is also worth ordering, as is a glass of the Hart brothers’ own Manzanilla to enjoy while queuing.

The cuisine of China’s Xinjiang region is celebrated at Camberwell’s Silk Road. The room is brightly lit, tables are communal and the menu is refreshingly short. Visitors will also struggle to spend over £25 per-head. Fried pork dumplings are an essential, plus handmade belt noodles to hoover the Dapanji’s spicy broth, and skewers of grilled kidneys or ox tripe shish: not unlike octopus, but with unmistakable bovine intensity.

Thuy Nguyen’s cafe on Old Kent Road does serve oustanding Hanoi pho of clarity and depth; it does serve crackling rare beef salads and fried duck tongues. But its crowning glory — only available from the Vietnamese-only blackboard as a special — is its offal platter, boiled or fried, with blood sausage and intestines aplenty ready to be dipped into mam tom, the concrete-grey shrimp paste whose colour belies its intensity.