All trains have been stopped at Peterborough due to a trespasser on the tracks this afternoon, Monday.
#LNER tweeted: "Due to a trespasser at #Peterborough, all lines are currently blocked.
"We will provide more information when we have it."
UPDATE: A spokesperson for London North Eastern Railway has said disruption caused by trespassers on the railway at Peterborough has now ended.
"Services are no longer affected by this problem."