The Telegraph carries a report on what is assumed is the first curry house in the UK.

But according to a recent discovery, he could well
have done. Historians have found that Britain’s first Indian restaurant
was opened in 1809, in the midst of the Napoleonic wars and during the
period in which Austen set Pride and Prejudice.

The
Hindoostane Coffee House was established by Sake Dean Mahomed, an
Indian-born entrepreneur, as a purveyor of Oriental food of the
"highest perfection" in Marylebone, London, which at the time was a
residential district for the well-off.

In one way, not all that surprising, that the East India Company brought a little of India back to the UK. But the date is odd. For, at that time there was no habit of eating out at all. Lunches for merchants in The City perhaps, coaching inns for travellers, but in 1809 it may well have been not just the first curry house but the first restaurant at all in London.

As the article notes, it failed for precisely this reason, no culture of dining out. But I’m not sure if there actually is evidence of restaturants before this. If you have some, let me know.