Italian centre-left alliance boosted as another group signs up

FILE PHOTO: Enrico Letta, the head of the centre-left Democratic Party (PD), smiles during an interview with Reuters about the forthcoming national election that was called after the surprise collapse of Mario Draghi's unity government, in Rome, Italy, July 25, 2022. REUTERS/Remo Casilli

ROME (Reuters) - The Italian Green leftist federation on Saturday agreed to join an electoral alliance led by the Democratic Party (PD), in a move seen as strengthening the centre-left ahead of an election next month.

The ballot is set for Sept. 25 and polls show a conservative alliance is on course for victory, with the far-right Brothers of Italy set to be the largest single party. Italy's election law favours parties that form broad alliances.