Network Rail has defended its decision to schedule engineering works for the first May bank holiday.
It said work on the tracks at Gatwick on May 6 and 7 is ‘crucial’ to a new timetable set to be rolled out on the Brighton Mainline next month.
The works – which take place on the opening weekend of the Brighton Festival – will involve essential work to replace tracks in the Gatwick area.
And it added there was ‘no good time’ for engineering work, but that it consults rail operators to choose the most appropriate times for closures.
But the timing of the works, which will see no rail services between London Victoria and Brighton on Sunday, May 6 and Monday, May 7, has come in for criticism.
Some campaigners said the move could impact on the city's economy.
Chris Todd of Brighton and Hove Friends of the Earth (BHFOE) said: “The May bank holiday weekend is one of the busiest in the calendar. Apart from being a popular time for people to visit the city, it’s also the start of the Brighton Festival.
“We already have a problem with too many people driving into the city. We need Network Rail and rail operators to be increasing services, not bringing the city to a grinding halt.”
BHFOE is calling on Brighton and Hove City Council, the city’s MPs and the Chamber of Commerce to get behind a campaign to get services reinstated and the engineering works rescheduled.
Caroline Lucas, Green MP for Brighton Pavilion, backed the calls, and said: ““The timing of these engineering works really couldn’t be any worse. I urge Network Rail to rethink these plans.”
Peter Kyle, Labour’s MP for Hove, said the move had put ‘a spanner in the works’ in the city’s plan to open for business to tourists after a ‘long, hard winter’.
He added: “I’ve written to the John Halsall, the route managing director, to ask that the work is moved to a different weekend. Let’s celebrate summer coming and get our tourist trade busy!”
A Network Rail spokesman said: “We are acutely aware of the pressure on the Brighton Mainline, with huge numbers of trains and passengers every day.
"There is no good time to work on the line, especially when that work is going to take more than a day or overnight.
"By undertaking this work on a bank holiday weekend, we can keep the railway open on the Saturday and avoid closing the line for a complete weekend at a later date.
"There is never a quiet time on that railway and by doing this work we can keep trains running reliably for the future.”
For details of changes to the Southern and Thameslink timetables on May 20, visit: www.railplan2020.com