A railway line is blocked due to flooding after torrential rain.
The Lewes to Haywards Heath line is blocked in both directions as a result.
Southern Rail said no trains will stop at Plumpton and Cooksbridge until further notice.
A spokesman said: "There's been a lot of rain this morning and unfortunately the line between Lewes and Haywards Heath is blocked in both directions due to flooding.
"Trains between Ore/Eastbourne and London Victoria will be diverted via Brighton.
"At this time, there are no replacement buses available to serve Plumpton and Cooksbridge."
The Met Office issued a yellow weather warning for rain from midnight until 3pm.
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