City councillors received the bad news in an independent report today advising that the project will cost at least £700m to complete a much shorter line or up to £750m to cancel the project completely.

Soaring cost-overuns and delays have split the council with the SNP calling for the scheme to be scrapped and Lib Dem and Labour councillors arguing it should be completed.

Councillors will discuss the fate of the project at a crucial meeting next week.

The third and most costly option is build the line to St Andrews Square for a cost of between £720m and £773m, which would see the ill-fated project delivered £200m over budget.

This would leave the City council facing a financial squeeze but could be the most favourable of the three options because it would earn £2m a year in profits, according to the report.

Under this plan, trams would start running by early 2014, four years later than originally planned.

Eighty percent of the £545m budget has already been spent with huge sections still incomplete.

A bitter dispute between the tram company Tie and contractor Bilfinger Berger pushed the project over budget and behind schedule.

Conflicts have been blamed largely on utility companies failing to keep accurate records of underground pipes and a badly drafted original contract.

Although the German contractor recently agreed to relay sections of track in the city at no extra cost.

Construction began in 2008 and the line which was due to run from Edinburgh airport through the city centre and eastwards to the old port of Newhaven.

The council has already approached the Scottish government to discuss borrowing the extra money it needs and is considering loans from the private sector.