MILAN (AFP) – A contested high-speed train line between Italy and France has become a key battleground for a divided populist government in Rome, with part of the coalition demanding the project be scrapped. Business leaders are expected to lead a rally on Saturday urging Rome to forge ahead with the 8.6-billion euro ($9.8-billion) tunnel through the Alps for the line linking Turin to Lyon, which has already been partially dug. The rail link will reduce travel time between Milan and Paris from almost seven hours to just over four. As well as being attacked by environmentalists, the line has been criticized as a misuse of public funds and the anti-establishment Five Stars Movement (M5S) had pledged to block it if elected. But its government partner, the far-right League, favors the venture and the movement now fears the so-called TAV may join the growing list of promises it has been forced to break. With furious M5S voters burning its flag over other perceived betrayals, analysts have warned a go-ahead on the line could be devastating, particularly for populist leader and deputy prime minister Luigi Di Maio. ''Italy is the second largest manufacturing country in Europe, and it is in its interest to have large-scale infrastructure,'' insists Vincenzo Boccia, head of the industry lobby Confindustria. Turin's city hall – run by the M5S – voted against the line last week, as protests raged outside. The following day, the Piedmont regional council – where the centre-left has the majority – voted in favor. Piedmont head Sergio Chiamparino has said he is ready to hold a referendum on the issue to decide once and for all, while supporters of the project are to demonstrate in Turin on Saturday, along with local French politicians.