The remark actually referred to St. Paul's coming down to Brighton. I've left out the reference to Brighton for obvious reasons.
Sydney Smith (1771–1845) was an English clergyman, critic, philosopher and wit. This undeniably witty remark about Brighton Pavilion is commonly attributed to him, but I have been unable to find any attribution that's anything like contemporary with him. And the quote is slightly different every time, which suggests to me that there is no definitive attribution.
The Oxford Dictionary of Quotations cites as its source The Sayings of Sydney Smith (1993), by Alan Bell. The Oxford Dictionary of Humorous Quotations (edited by Gyles Brandreth) cites Peter Virgin, Sydney Smith (1994). Few other Internet sources (including Wikipedia) seem to attribute the quote to Smith at all.
One blog, interestingly, does attribute the remark to Smith, but also says that the Member of Parliament and anti–slavery campaigner, William Wilberforce (1759–1833), wrote: "The Pavilion in Chinese style – beautiful and tasty, though it looks very much as if St Paul's had come down to the sea and left behind a litter of cupolas." It adds, rather perspicaciously: "These quotes are so similar that it seems likely that one was derived from the other."
But who said it (or wrote it) first? If you know, please enlighten me!
© Haydn Thompson 2017