This is when the East Coast Main Line between Peterborough and London will be shut

The £1.2bn upgrade is the biggest seen on the route for 20 years and is set to create capacity for up to 10,000 extra seats a day on long-distance services, see faster journeys and improve reliability for passengers.

Early route improvement work has already taken place, but the first major engineering upgrade will mean no trains are able to travel between Peterborough or Cambridge and London King’s Cross or London St Pancras International during the August Bank Holiday weekend.

As well as the August Bank Holiday closure, there will be a slightly reduced service on the weekend of 13/14 July for work to be carried out to remove signalling equipment from a disused railway tunnel ahead of laying new track. It will eventually increase the number of tracks into King’s Cross station from four to six.

Rob McIntosh, Route Managing Director for Network Rail, said: “We are delivering the biggest upgrade to the East Coast Main Line in a generation to bring huge benefits for passengers – including additional seats, quicker journeys and a more reliable service.

“We know this work will have an impact on people who use the line – we’re doing everything we can to keep disruption to a minimum, but passengers will need to plan ahead and check before they travel.

“Once completed, this upgrade will improve journeys and ensure we can continue to provide a service which meets the needs of the passengers, communities and economies we serve.”

Over the Bank Holiday Weekend, major work is taking place between Peterborough and London King’s Cross, as well as a track renewal in Newark. Passengers using services which start or terminate in the capital are strongly advised not to travel on 24/25 August and to instead travel on Friday, 23 or Tuesday, 27. Work at Newark will continue on Monday, 26 August which means a reduced train service will run.

Passengers can see how their journey will be affected by visiting http://eastcoastupgrade.co.uk/. The rail industry is working together to keep passenger disruption to a minimum by carrying out work at multiple locations along the route at the same time.

A spokesperson on behalf of train operators along the route said: “Passengers are strongly recommended to plan their journeys well in advance of the August Bank Holiday weekend. Customers should avoid travelling to or from London King’s Cross, or between Cambridge and London St Pancras, on the Saturday and Sunday. Other routes into the capital will remain available, but could be significantly busier than normal.

“New trains are going into service on the route, and new trains need new infrastructure. This is essential work that will allow more trains to run and provide quicker journeys on long-distance services.”