The compass rose (by Giles Blomfield) is a symbol of the Anglican Communion world wide - more than 70 million Anglican Christians in 38 Provinces spread across 164 countries. It lies in the floor at the east end of the nave where it was dedicated by Archbishop Robert Runcie at the farewell eucharist of the 1988 Lambeth Conference. It appears to be a compass but it points to the east end of the cathedral, not north. The Greek inscription (the language of the New Testament) reads 'The truth will set you free'. The symbol led to creation of the Compass Rose Society, which offers financial and other assistance to those in poorer parts of the Anglican Communion abroad. The origins of the rose can be traced to work by Edward West, canon of New York cathedral, in the 1950s.
Sources: see standard cathedral sources