Trains travelling to and from London King’s Cross were delayed by up to 40 minutes on Thursday evening following a “trespass incident” near Peterborough.
National Rail said lines were forced to close while the incident and services could also be cancelled or revised.
Routes impacted include CrossCountry services between Birmingham New Street and Stansted Airport, and Grand Central trains between King’s Cross and Bradford Interchange, as well as to Sunderland.
Trains from King’s Cross to Hull and Beverley are also impacted as well as LNER services from the London station to Lincoln, Leeds, Harrogate, Skipton, Sunderland and Edinburgh.
Earlier on Thursday Stansted Express trains running between the London airport and Liverpool Street Station were disrupted by an “operational issue”.
