The deal is part of a three-year strategy plan ironed out earlier this year by TIM CEO Luigi Gubitosi aimed at reviving Italy’s biggest phone group which is saddled with more than 25 billion euros (£21.79 billion) of debt.

TIM and Vodafone entered into an exclusivity agreement in February to evaluate combining their 22,000 telecom towers in Italy into a single entity.

The deal will also include a partnership to enable faster deployment of fifth-generation mobile phone services over a wider geographic area and at a lower cost.

"A signing is expected during the summer," Ferigo told an analyst call after INWIT's first quarter financial results.

The combining of Vodafone's towers into INWIT would leave TIM and Vodafone with equal shareholdings and governance rights in INWIT and ensure there is no obligation for either to launch a tender offer for INWIT’s remaining shares.

(Reporting by Elvira Pollina; Editing by Kirsten Donovan)