Luigi (Joseph Long) is the owner of a basement trattoria directly opposite the façade of the Fenchurch East police station. Given its proximity, the CID dine and/or drink there after work, and DI Alex Drake resides in a flat upstairs. An Italian immigrant, he is at times either visibly irritated, exasperated, or amused by DS Ray Carling's and DC Chris Skelton's ethnic humour and DCI Gene Hunt's general abuse. He detects that Hunt and Drake are attracted to each other, and repeatedly encourages Hunt to pursue those feelings. He is quite fond of his neighbour, Drake. He cooks her veal scaloppine using his late mother's special recipe for the sauce which he does not serve to the other police officers who frequent his trattoria. "Pearls before swine," he explains.

In episode 1.6, "Over the Hill", Hunt coerces Luigi to open the trattoria in pre-dawn hours in order that Hunt and Drake can hold a small, impromptu birthday party for eight-year-old murder witness, Donny Cale (Asa Butterfield). Like Drake, he lives in a flat above the restaurant and, after the food is served, tells Hunt to lock up so that he can go back upstairs to bed.

In the final act of episode 1.7, "Charity Begins at Home", Gil Hollis fires several shots into Luigi's restaurant from in front of the police station, leading a determined Hunt to declare that, "I am not dying in a trattoria!"

As of November 1982, Hunt has a substantial bar tab at Luigi's.