Transport for London has begun talks over the possibility of extending the Elizabeth line east of Abbey Wood into Kent.

Mayor of London Sadiq Khan said options to extend the line from Abbey Wood to Ebbsfleet were now in development, and that TfL had begun discussions with Network Rail over moving forward with the scheme.

Responding to questions from London assembly members, Mr Khan said: “Options to extend the Elizabeth line from Abbey Wood to Ebbsfleet are still being developed and engagement with the rail industry is in its early stages.

“Transport for London has started discussions with Network Rail as the infrastructure owner of the mainline national railway network and, once proposals have progressed sufficiently, will engage with other freight and passenger operators, most likely once the new Southeastern franchise has commenced later this year.”

The extension would see Crossrail continue 28 km east of Abbey Wood to Ebbsfleet, with the option of stopping at stations in Dartford and Bexley.

The questions came from London Ukip assembly member David Kurten, who asked whether the extension would be on new or existing tracks.

Mr Khan said options were still being developed, and a decision on if and when the extension would take place would be dependent on whether funding could be found.

The mayor said: “The delivery date of the scheme is dependent upon whether a successful business case can be made and a suitable funding package identified.

“Work is currently under way to investigate both the case and possible funding sources for a potential extension to the Elizabeth line.”

Mr Khan has previously said an extension of the Elizabeth Line east of Abbey Wood should be a priority, and that a strategic outline business case for the scheme could be submitted later this year.

When asked by Mr Kurten whether an extension to Ebbsfleet would only take place if projects such as the Bakerloo extension and Crossrail 2 were finished, Mr Khan said this was not the case and that any work would be dependent on affordability and a strong business case.

The government is currently carrying out an Independent Affordability Review looking into ways to make Crossrail 2 more financial viable.

The review team, which is being led by former Tideway managing director Mike Gerrard, will submit an interim report in the summer before publishing its full report later this year.