Passengers have been warned of delays and cancellations to trains on the London Paddington mainline after trespassers were spotted on the tracks.
Trains between London Paddington and Reading are operating at reduced speeds and some lines are blocked, according to Great Western Railway. National Rail said disruption to services was expected to last until 7pm.
Elizabeth line, Great Western Railway and Heathrow Express services are all affected by the issue, the company said.
An update on National Rail’s website said: “There are trespassers on the railway in the Southall area, meaning that trains must run at reduced speed on all lines for safety reasons.
“As a result, trains running between London Paddington and Heathrow Airport / Reading may be cancelled, delayed by up to 40 minutes or revised.
“This issue is expected to continue to impact services until 19:00.”
Trespassers spotted in the West Drayton area also caused disruption to services on Wednesday last week (October 15).
For the latest travel information, visit the National Rail website.