From 12th January 2015-August 2016 trains to Charing Cross will not be stopping at London Bridge. Southeastern services from New Cross, Deptford and St Johns to Charing Cross will be diverted permanently to Cannon Street and some services from Lewisham and other stations will also be diverted.
From August 2016-early 2018 the situation will be reversed and Cannon Street services will not stop at London Bridge.
There are also various temporary changes taking place around Christmas.
Clearly these changes will have a major impact on people's journeys, so I am advising any constituents who need to travel on one of these routes to check the Thameslink Programme website at www.thameslinkprogramme.co.uk. You can enter the name of the station from which you are travelling and the site will tell you how your journey is going to be affected.