LONDON - The remains of five archbishops of Canterbury have been accidentally discovered by builders in a hidden tomb beneath a London church, site developers said on Sunday.

Some 20 lead coffins were discovered in a crypt underneath St Mary's-at-Lambeth, which sits outside Lambeth Palace, the central London residence of the archbishop of Canterbury - the highest cleric in England.

Two have been identified from name plates, while records show that five were buried in the crypt.