After nearly a week of delayed and cancelled trains, services are returning to normal today for Thameslink passengers and a full service is in operation on East Midland Trains.

Engineers successfully tested and brought into service a new signalling control system after the old one was damaged beyond repair by a power surge.

The disruption happened on Monday and many Thameslink services, which go through St Albans and Elstree and Borehamwood, were cancelled or delayed.

Rob McIntosh, route managing director for Network Rail, said: “I want to thank passengers for their patience while we carried out this complex repair. My team and I are genuinely sorry for the disruption they have faced this week and have worked around the clock to restore services as soon as quickly as possible.

“The signalling equipment which was damaged beyond repair is an essential part of how we move trains safely so we needed to carry out methodical and meticulous testing overnight to make sure that it is working as it should.

"I am pleased that this has gone as planned and that services will be able to return to normal.”

Owing to the level of disruption caused by this incident there are still alterations to Thameslink services today. Thameslink aims to run a normal service between Bedford and Brighton, and between Sevenoaks and London.

However, there will be a reduced stopping service between Luton and London St Pancras, and between Sutton/Wimbledon and London Blackfriars as the service recovers.

Jake Kelly, managing director for East Midlands Trains said: "We know that many of our customers will have had very difficult journeys this week and we would like to thank them for their patience during a challenging few days.

"I'm pleased that we are able to return to our full and normal timetable today."

Thameslink passenger services director, Stuart Cheshire, said that it has been a long and difficult three days for the Thameslink passengers and staff who will be relieved now to learn that Network Rail has repaired this major fault.

He said: "The effect on our service has been severe, especially north of London where we have had to cut back the number of trains to just a few an hour between Bedford and St Pancras, and also reduce the service to and from Sutton and Wimbledon. I would like to thank people for their patience."

Anyone whose journey was delayed by 30 minutes or more can claim compensation from either Thameslink or East Midlands Trains websites.