In this Act, " the Port of London " means the port of that name appointed for the purposes of the enactments relating to customs or excise, together with all such waters between—
(a)the seaward limit of the port as so established, and
(b)imaginary straight lines drawn from latitude 51° 37' 00" north, longitude 00° 57' 19" east (Foulness Point in the county of Essex) to latitude 51° 46' 05" north, longitude 01° 20' 32" east (Gunfleet Old Lighthouse) and thence to latitude 51° 26' 36" north, longitude 01° 25' 30" east and thence to latitude 51° 24' 55" north, longitude 00° 54' 21" east (Warden Point in the county of Kent),
as are for the time being within the territorial waters of Her Majesty's dominions.