<Tr> <Th> Brampton </Th> <Td> (0169 77) xxxx </Td> <Td> (069 77) xxxx </Td> </Tr> <Tr> <Th> Southampton </Th> <Td> (01703) xxxxxx </Td> <Td> (0703) xxxxxx </Td> </Tr> <Tr> <Th> Inner London </Th> <Td> (0171) xxx xxxx </Td> <Td> 071 - xxx xxxx </Td> </Tr> <Tr> <Th> Reading </Th> <Td> (01734) xxxxxx </Td> <Td> (0734) xxxxxx </Td> </Tr>

When did telephone numbers change to 6 digits