Train passengers from Brighton, Hove and Portslade will be unable to travel directly to London Bridge on Southern services over the bank holiday weekend.
But First Capital Connect will be operating Thameslink services to London Bridge.
Southern said: “From 1.25am on Saturday 25 May at to 4am on Tuesday 28 May platforms 8 to 13 at London Bridge Station will be closed due to engineering works as part of the £6 billion Thameslink programme.
“This means that all Southern platforms at London Bridge will be closed during the May Bank holiday.
“But First Capital Connect and Southeastern will continue to serve London Bridge station during this weekend.
“On Tuesday 28 May platforms 8 to 13 will be back in full operation while platforms 14, 15 and 16 will continue to be closed in line with the new May timetable.”
Engineering work will also take place overnight from Saturday 25 May to Sunday 26 May between Earlswood and Gatwick Airport.
Southern said that it would run a Saturday service on Monday 27 May.
First Capital Connect has appointed a new managing director. David Statham, 44, is due to take over from Neal Lawson, who leaves on Friday 24 May to join Network Rail.
Parent company First Group said: “David has an extensive record of leadership and delivery within the rail sector, having held a number of senior roles with a strong focus on customer service and major project delivery.
“He has considerable experience of close partnership working with a wide range of stakeholders, which will be invaluable in his new position, and was responsible for First Capital Connect’s central role in the initial stages of the Thameslink programme.
“Most recently David led the development of FirstGroup’s strategy for the expanded Thameslink, Southern and Great Northern franchise, which resulted in the group being one of the shortlisted bidders for the current competition.”
Mr Statham, a 44-year-old father of two, led First Capital Connect’s team implementing the first stage of the Thameslink programme from 2008 to 2011.
This brought new and longer trains to the Brighton to Bedford Thameslink route, including the first 12-carriage services. It also involved the revamp of Blackfriars Station.
Mr Statham said: “I look forward to leading the team at First Capital Connect as we continue to improve the service we offer our customers and deliver considerable further infrastructure and capacity increases for our passengers, partners and stakeholders.
“I am determined to focus on improving customer satisfaction, which is at the heart of all our business decisions, by delivering solid performance, a clean train environment and the best possible response and information during times of disruption.”
Vernon Barker, FirstGroup’s UK rail managing director, said: “I am delighted to welcome David to his new role.
“He will lead the First Capital Connect team at a crucial time as the return to rail franchising gathers pace and we move ahead with the next stage of the Thameslink programme.
“I would also like to thank Neal for the significant contribution he has made to our business.
“He leaves First Capital Connect in great shape for the next phase of the franchise and we wish him all the best for the future.”
