A fire next to the track between Alexandra Palace and Stevenage means some lines towards London are blocked.

Trains running between London and Stevenage will be cancelled, delayed by up to 30 minutes or revised.

Disruption is expected until 12:45.

Great Northern and Thameslink customer advice:

If you are travelling now, you may need to use an alternative service to arrive at your destination and your journey will be delayed by at least 30 minutes. Please allow extra time and check your journey before you travel.

Great Northern and Thameslink are unable to call at Knebworth and Welwyn North in the direction towards London.

• If you are travelling to Knebworth or Welwyn North from the Stevenage direction, please remain on the train until Welwyn Garden City, where you can change to a train towards these stations. These trains run every half an hour
• If you are travelling from Knebworth or Welwyn North to London, please take a train to Stevenage and then change there for southbound services

Service alterations:

Some services that normally run between Peterborough and Horsham / Cambridge and Brighton may be diverted via Hertford North after Stevenage.

Some services may not call at all their usual stops, so please check the information boards and listen out for announcements for the latest information.

Ticket acceptance:

You can use your ticket at no extra cost to travel on alternative Great Northern and Thameslink services between Alexandra Palace and Stevenage.

Planning your journey:

Please check journey planners and station information boards before you travel, and allow extra time to reach your destination.

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 the Thameslink app to find up-to-date information.

Can you tell me more about the incident?

We've had a report of the fire brigade dealing with an incident near the railway. To allow this to be done safely, some train services will be altered when running through this area.

This will lead to some delays, so your journey is likely to take longer.

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.