Two major London stations are set to shut for three weeks this summer as part of a £20million upgrade, with commuters warned to expect disruption. London Charing Cross and Waterloo East will close from Sunday, July 26 until Sunday, August 16, while engineers carry out major improvement works. The closures will affect Southeastern services, with trains that normally run into Charing Cross being diverted to London Victoria, London Cannon Street and London Blackfriars instead. Some services will also terminate at London Bridge. Passengers are being urged to check their route before travelling, as alternative services will be in place throughout the closure. Here’s everything we know about the works. When are the stations closing? The main closures will last 22 days, from Sunday, July 26 to Sunday, August 16, to coincide with the summer holidays. But there will also be additional weekend closures before and after for preparation and follow-up work: Network Rail has warned that travel arrangements on these extra closure dates may be different from the main 22-day closure, so passengers should check …