Train passengers are now being treated to a preview run of the new service linking Finsbury Park to London Bridge, Gatwick and Brighton.

The six “preview” journeys – three in each direction throughout the day – travel through the new tunnels linking Finsbury Park to St Pancras ahead of the full rollout in May.

Those on the first journey for the brand new 12-carriage trains this morning were also treated to a cupcake from operator Thameslink.

Most of the trains will replace existing Great Northern or Thameslink services and departure screens will show new end destinations, which could be Brighton or Horsham southbound or Peterborough or Cambridge in the opposite direction.

When the full service is up and running, it will cater for 40,000 more passengers. Services will run from 80 more stations and the new tunnels mean passengers won’t have to change to get on the St Pancras line.