A final decision on whether to extend the tram line in Edinburgh has been delayed until next year.

An outline business case to create a new £165m line connecting Leith and Newhaven to the existing York Place station was approved in September 2017.

However, a final decision has now been pushed back until March 2019, three months later than previously planned.

Tenders for the project were received in early September, with an announcement due to be made in December.

An extended line to Newhaven is projected to transport almost 14 million passengers in its first year of operation, more than double the numbers on the current service, which runs to Edinburgh Airport.

Transport convener Councillor Lesley Macinnes said: "We have adopted a very thorough and robust process for the trams to Newhaven project throughout, learning crucial lessons from what went wrong previously.

"We have been very clear from the outset that we will not bring forward the final business case for tram until we have vigorously tested the cost and time estimates with the market."

Construction of the extension will cause considerable disruption, with three lanes of Leith Walk street closed for around 18 months.

Edinburgh City Council said it had consulted with residents and firms in Leith and Newhaven,and has also proposed a £2.4m support package for businesses.

Vice-transport convener Councillor Karen Doran said: "It is important for the council to have sufficient time to undertake due diligence and comprehensive evaluation of the final submissions and we have therefore decided to take extra time to allow this process to take place.

"We have also asked officials to extend the ongoing consultation period on the project design and plans until November 11 to ensure maximum participation and we look forward to the final business case being presented to councillors for a decision in March 2019."

An inquiry has been held into construction of the original tram line, which was besieged by difficulties.

The probe, chaired by Lord Hardie, is examining why the trams were delivered late, over-budget, and with a truncated route.

The final cost of the project, at £776m, was more than double the sum earmarked at the outset.

Trams finally began running in Edinburgh in May 2014 - six years after construction began.