Heritage Open Day: In Toxteth , at the Mother Church for South Liverpool's Catholics, you can see One of the finest altar pieces in the United Kingdom - The Crucifixion by Niciase de Keyser of Antwerp c 1834. Built 1821-1827 by public subscription and designed by John Slater , this large church , the oldest Catholic church in Liverpool now in use, is dominated by four Greek Doric columns which form a porch at each of the two West End entrances below a very prominent statue of its patron , St. Patrick . It is built of brick with stone dressings , to an unusual , cruciform plan . Pevsner says that the interior is similar to that of a Nonconformist chapel with its two tiers of windows and galleries on three sides.