A fault with the signalling system between London Victoria and Clapham Junction means some lines are blocked. As a result, trains may be delayed by up to 10 minutes or revised.

Disruption is expected until the end of the day.

Customer Advice:

If you are travelling now, you can continue to use your normal route to reach your destination. Your journey may take up to 10 minutes longer than usual, so please allow for extra time.

Trains which usually run between Portsmouth Harbour / Bognor Regis and London Victoria will instead be diverted to London Bridge. These trains will no longer call at Clapham Junction or London Victoria.

If you are travelling to or from either of these stations, you will need to use an alternative service to East Croydon, then change there for a service towards your destination. Alternatively, you can use your ticket to travel on London Underground services to London Bridge, where your train towards Portsmouth / Bognor Regis will now depart.

Please check journey planners and station information boards before you board, and ensure your train will call at your expected destination.

You can use your ticket to travel at no extra cost on:

• Alternative Southern services on any reasonable route towards your destination.
• London Underground services on any reasonable route.

Planning your journey:

You can see a live map of the network here. This will show where your journey is likely to be affected.

You can also use Southern's app to find up-to-date information.

Can you tell me more about the incident?

This part of the network uses track circuits to detect trains. If a circuit fails, the system may think a train is still there, blocking others from moving forward.

In this case, drivers must stop at a red signal and get verbal permission to proceed at a reduced speed. This may cause some delays, especially in areas with long track sections.

Faults can be caused by a number of reasons, including electronic issues or track obstructions. Network Rail is investigating, and we’ll share updates as soon as we have them. Thank you for your patience this afternoon.

Check before you travel:

You can check your journey using the National Rail Enquiries real-time Journey Planner.

Compensation:

You may be entitled to compensation if you experience a delay in completing your journey today. Please keep your train ticket and make a note of your journey, as both will be required to support any claim.