Goodbye Oyster Extension Permits

"From 22 May, passengers using a London Oyster Travelcard who want to travel outside their travelcard zones will no longer be required to load an Oyster Extension Permit onto the Oyster Card. The permits were intended to indicate an intention to to extend travel using Oyster pay as you go (PAYG) credit. Although free of charge, the permits ... caused widespread confusion." [Modern Railways, April 2011]