Plans to build a £600 million tram route connecting Kent and Essex have taken a significant step forward with the publication of plans for an interchange and projected revenue and operating costs.

The KenEx project would see a route running between Bluewater and Lakeside, through a 1km tunnel under the River Thames, and one between Dartford and Gravesend.

Currently there are three options for the second route, the preference is for a £122m line stopping at Northfleet, Swanscombe and Greenhithe with an interchange (pictured) outside Ebbsfleet United’s Kuflink Stadium.

According to Professor Lewis Lesley — who is working on the project and was involved in the design of a £25m tram in Preston — the operating cost of that route would be £6.2m a year, while it would make £14m.

When coupled with the £472m route between Bluewater and Lakeside, which would cost £5.2m and make £18.2m every 12 months, within 40 years KenEx would pay for itself.

Those behind KenEx have said they’re confident they can attract private funding.

The tunnel part of the project would see 10 100-metre, 10,000-tonne sections constructed in a dry dock at Tilbury, floated into the river and sunk into place.

Prof Lesley said the whole construction stage would take less than a year and the sinking would take about 10 days.

He added the need for the tram is clear to see, with similar schemes like FastTrack already at saturation point having attracted 1.2 million passengers a year and the multi-billion pound Lower Thames Crossing still nine years away.

KenEx could be up and running in half that time.