Flicking through the 2009 fares leaflet at
http://www.tfl.gov.uk/assets/downloa...s-zones1-6.pdf the
online version states that:

"Your Tube, DLR, London Overground and National Rail
pay as you go journey must be completed within
a time limit from when you touched in at the start
of your journey. The time limit varies between
70 minutes for the shortest journeys on Monday to
Friday and four hours for some longer journeys on
Sunday. If the time between touching in and touching
out at the end of your journey is more than the time
limit you will be charged more than the Oyster single
fare for your journey. If this happens, you will need
to call the Oyster helpline for assistance."

My printed copy of the leaflet has a fixed time of "two and a half hours".

When did this change?

David