http://news.bbc.co.uk/1/hi/england/london/6215701.stm

Stations on a section of the Central Line will be re-zoned from 2
January in an attempt to raise passenger numbers.

Barkingside, Fairlop, Hainault, Grange Hill, Chigwell and Roding
Valley, in east London, are being moved from zone five to zone four.

The stations, which form the Hainault loop, are being re-zoned to
attract more passengers, Tube officials said.

By making the change, passengers travelling between the stations and
central London will pay lower fares.

General manager for the Central Line, Jeff Ellis said: "Passenger
numbers on this part of the line have traditionally been low compared
to other parts of the Tube network."

He said their aim was "to increase passenger demand on this section of
the Central Line".

Last month services to the Hainault loop were extended and the route
began operating beyond 2000 GMT.