this is a cool page which calculates and displays the time difference between London, UK and other cities. this page takes into consideration the time zone offset of the cities.

http://www.happyzebra.com/timezones-worldclock/difference.php?city=London

this is useful if you are planning to visit UK or doing business with companies in the UK. the page also displays the dialing codes to London, UK and current time in London.