In a statement released earlier today (18 June), the restaurant thanked its guests, staff and suppliers for all their support, and said it was truly sorry to be closing its doors for good.
It said: "Sadly, despite government support and an understanding landlord, we are unable to see a path to reopening. For our small space any kind of social distancing would be very difficult to implement and we do not have the resources to trade through the inevitably difficult times ahead.
"Sardine would have been four years old on 5 July, and in ordinary times we would be planning a party. We had a lot of fun over the years, and are immensely proud of the great times that we have created for our guests and our employees.
"Whilst there are no future plans at all right now, we know that Londoners will always have an appetite for the honest, delicious cooking and warm hospitality that Sardine brought to the city, and we hope that someday and somehow we will be able to cook for you all again."
Sardine, which was opened by Jackson and chef restaurateur Stevie Parle back in 2016, focused on the flavours of Southern France.
Dishes to have featured on the ever-changing menu include pork shoulder cooked in milk with green polenta and crispy sage; hand-made malloreddus pasta with salami, dandelion and ricotta; and leg of lamb à la ficelle with white beans and anchovy.
The announcement of its closure comes in the same week that it was confirmed that Mayfair's Indian Accent, and the legendary Le Caprice in Piccadilly will also not reopen once lockdown is lifted.