Roger Harding, general manager of Tramtrack which runs Croydon's trams, said: "They do have an outline plan of where they want it to go. I think it would be extremely useful and popular. "We would definitely see it as a very worthwhile challenge." Mr Harding revealed he had knowledge of the plan though TfL has not yet shared its route ideas with his company.

If this new extension went ahead alongside Croydon's extension to Streatham the two projects could feasibly be linked.

This would create a super-tram line connecting commuters in Coulsdon with not only Euston but major central London stations Waterloo and King's Cross.

With any potential route still shrouded in mystery Mr Harding speculated it could run along much of the A23.

He said: "Personally, if it were up to me, there is potential to take the tram either side of Thornton Heath Ponds and to take it north along London Road and back along Wellesley Road."

He also suggested the council's preferred southerly route would run down the Purley Way, potentially joining the existing tram network at Ampere Way.

Councillor Chris Wright, Croydon's cabinet member for planning, Croydon Green Party, and Croydon Business have all backed the idea this week.

They feel that traffic problems on the heavily congested A23 would be hugely eased with a line linking Coulsdon and Purley with Croydon and Streatham.

Despite there being no TfL consultation on the route, Cllr Wright believes it is more likely to go ahead than Cross River.

He said: "I'm a little sceptical of Cross River. The Coulsdon to Streatham line is a much more sensible idea.