Paddington
No, it's not. The o2 arena is in Greenwich, London, with slough being a part of Berkshire. You're not too far off though. Jump on a train at slough to London Paddington and hop on the tube. The whole journey should take you about an hour at most.
The project you may be thinking of is called crossrailconnecting Essex with Berkshire via Liverpool Street, Oxford Circus, and Paddington. The project is now financed, but the service won't be running until at least 2015.
There are about 91 miles between Slough, UK and Eastbourne, East Sussex, UK.
Tokyo is 8 hours ahead of Slough.
I guess it depends on when you want to travel, but on a normal weekday morning it will take just less than 2¼ hours, changing at Paddington and London Bridge.
The Adventures of Paddington Bear - 1997 Paddington Makes a Clean Sweep Paddington and the Olympics Paddington and 'Do It Yourself' was released on: USA: 2 August 2009
Slough is located in Slough
Five miles
Slough and Birmingham are both locations within the United Kingdom. It is 87 miles in distance between these two locations.
The Adventures of Paddington Bear - 1997 Paddington at the Wheel Howdy Paddington A Shopping Expedition was released on: USA: 16 October 1997
The Adventures of Paddington Bear - 1997 Paddington Cleans Up Riding High Paddington Dines Out was released on: USA: 6 November 1997