A number of incidents on various Thameslink trains today have led to disruption across the entire network.
An ill passenger on a train at London St Pancras, and faults on two trains at City Thameslink and Farringdon have culminated in delays along the route from Bedford to Brighton.
While all lines are open, National Rail warned: "Due to the location of these incidents, multiple cancellations and alterations and delays up to 40 minutes can be expected."
Customers have been advised to keep an eye on departure boards as platform alterations are likely.
The disruption is expected to continue until 8pm.
|Advice for customers|
Tickets will be accepted on the following services: