Caroline Ansell has told the rail minister there must be no change in peak hour trains from Eastbourne to London Bridge after the MP discovered there are plans to move the only two existing services from the key 8-9am time slot.
Proposed Network Rail timetable changes mean the Southern services would arrive in the capital either before 8am or after 9am from 2018 - hitting the ability of workers to get to their desks on time because no other trains would then arrive in that peak hour slot at London Bridge.
Caroline told Claire Perry in a meeting that the changes, which were published in a document called the Sussex Area Route Study, were completely unacceptable to rail commuters.
Officials have now been told by the minister to review the planned timetable due to take effect in two years’ time when work at London Bridge is completed.
"These changes have not been widely publicised and would have a major effect on the ability of commuters to get into this part of London for work and so are completely unacceptable and I made that point very clearly to the minister and her officials when we met," said Caroline.
"This is another unwarranted attack on rail services from our town that I intend to fight and it is very frustrating. These changes will shortly go out for consultation, so I urge everyone to make their feelings known.
"The service is bad enough already but what’s even worse is not being able to get into the capital every morning at a time that is convenient to start work.
"I was heartened to hear that the minister immediately asked officials to undertake a review of these proposed changes and I will ensure that I keep the pressure on to see they do not happen."
Caroline also spoke to the minister about other rail issues, including enhanced rail services both along the Coastway and to Brighton.
Claire Perry agreed that improvements for East to West links were under consideration including solutions to the connection to Ashford International in Kent.
"The Government is making unprecedented investment in rail to create a 21st century service while still operating such a busy schedule and we are feeling the pain arising out of massive engineering works at London Bridge," Caroline added, "But more has to be done to make our rail services better and I will continue to lobby hard to make sure these improvements are made."