Initially six off-peak services a day will operate through the new 1km link the low-level platforms at St Pancras International on the Thameslink core section with Belle Isle Junction near Finsbury Park station on the East Coast Main Line (ECML).

Most of these services replace existing Thameslink services south of London and Great Northern services from King’s Cross.

The connection between the Thameslink Core and the ECML comprises a 100m-long cut-and-cover tunnel outside St Pancras and a 600m-long twin-bore tunnel, which carries the line beneath the Regents Canal.