The Minquiers are a group of islands and rocks, about 15 km south of Jersey. They form part of the Bailiwick of Jersey.
They are administratively part of the Parish of Grouville, and of its Vingtaine La Rocque.The rock shelf around the Minquiers has a larger surface area than Jersey itself, but at high tide only a few of the main heads remain above water. The largest of these is Maîtresse, which is about 50 m long and 20 m wide and has about ten stone cottages in various states of repair. These are the most southerly buildings in the British Isles; but they have no permanent inhabitants; though fishermen, vraic collectors, yachtsmen, kayakers, and even radio amateurs make summer landfall.
Wikipedia https://en.wikipedia.org/wiki/Minquiers
Coordinates 48°58'54.92" N -2°7'18.174" E