Labour group transport spokeswoman Lesley Hinds said there were still question marks over key parts of the route. A big chunk of the £776 million price tag for taking the trams to St Andrew Square is for diverting utilities but the cost of such work has been one of the most problematic elements of the project.
And Councillor Hinds questioned whether a turning point for St Andrew Square had been fully costed – the tight corner from there to York Place was identified as “an engineering challenge” at an early stage in the project.
Cllr Hinds added: “I understand there is an issue about the width of the road at Shandwick Place. And further along Shandwick Place there are 500 utilities, 100 of them in conflict with the tramline.They have said they cannot guarantee the £776m won’t increase.”
Meanwhile, the Unite union, which represents workers at Lothian Buses, called for the project to be mothballed until a public inquiry is held. It said full and independently validated costings should be presented for all options on the future of the trams.