Even in a year when Sydneysiders have been hardened by the closure of some of the city's favourite eateries, the passing of restaurant institution BBQ King has rocked locals.

The restaurant, which opened when Malcolm Fraser was calling the shots in Canberra, was unflinchingly wed to a historic duck recipe yet chose a 21st century manner in which to deliver the news.

"After 40 years, BBQ King is sad to announce we have served our last Peking duck. We are so very humbled to have all of your support over these years. Thank you and goodbye!," it posted overnight on social media.

The restaurant's loyal tribe gathered online to pay respect, posting stories of their memories of first visits to BBQ King, its place in their hearts and stomachs. "Just when you thought 2020 could not get any worse," one customer wrote.

The Sydney restaurant world was equally shocked. Lucio's restaurant and the Perry family posted respects. BBQ King's appeal across all cultures and cuisines was evident, Australian-Italian chef John Lanzafame described the restaurant as "the best place I have ever been introduced to." "I can't believe it," Matt Moran added.

Many asked why? The impact of COVID-19 on restaurants generally – and the city in particular – can't have helped. The crisp-skinned duck specialist moved from Goulburn Street to Liverpool Street in 2016, turf historically considered more Sydney's Spanish Quarter.

"COVID, this just got personal," one regular moaned.