If industry analysts and investors are right, Vittorio Colao will become the next chief executive of Vodafone later this year. “Colao is running for office,” says one veteran observer of Vodafone.

Except that this is a very low-key campaign. Since he became Vodafone’s deputy chief executive in 2006, the charming Mr Colao has given no interviews to the media, partly because Arun Sarin, the current chief executive, is keen to avoid any public discussion of when he will depart.

Mr Colao, 46, is instead having to prove himself through Vodafone’s performance. His record as head of Vodafone’s European businesses, which generate 80 per cent of the UK group’s free cash flow, will be scrutinised when the 2008 results are published on May 27.

Analysts say there is already tentative evidence that he is combining the crucial tasks in Europe of increasing revenue and reining in costs.

Two former Vodafone board members say Mr Colao is the leading internal candidate to replace Mr Sarin. They add the only real alternatives are Andy Halford, chief financial officer, and Paul Donavan, head of emerging markets.

It remains unclear when Mr Colao might get the chance to take on the top job, although some Vodafone investors expect Mr Sarin to step down this year.

Mr Sarin is enjoying improved standing with investors because his big bets for Vodafone’s growth – led by investments in emerging markets – look to be coming good.

But two years ago he suffered a mauling in the media after Vodafone warned about slowing growth. For a while Mr Sarin’s position appeared under threat.

Mr Colao’s return to Vodafone as deputy chief executive and head of Europe was announced in September 2006, two months after an embarrassing protest vote against Mr Sarin at the group’s annual meeting.

Some observers claimed his appointment was instigated by Sir John Bond, Vodafone’s chairman.

But Vodafone insiders insist it was Mr Sarin’s choice to bring Mr Colao back to the company. They have known each other for more than a decade.

Mr Colao ended a four-year stint as a senior Vodafone manager in 2004 to become chief executive of RCS MediaGroup, the Italian publishing company that owns Corriere della Sera, the country’s leading broadsheet newspaper.

Although he improved profitability at RCS, Mr Colao clashed with some of its shareholders, who include several of Italy’s leading companies.

One shareholder claims Mr Colao’s weakness during his time at RCS was an unwillingness to compromise. “Once he takes a decision, he is not willing to talk any longer,” says the shareholder.

He agreed to step down as RCS chief executive in July 2006, having alienated too many of its shareholders.

Mr Colao’s time at RCS is the only less than wholly successful chapter in his career.

He is ambitious and clever, combining analytical skills with an ability to motivate people, according to former colleagues. They add he is principally a business man able to master a company’s operations, although he is also sound on strategy.

Two possible weaknesses are mentioned by people who know him. First, the unwillingness to compromise that came to the fore at RCS. Second, a propensity to micro-manage people.

Mr Colao was born in Brescia, northern Italy, in 1961 and is the son of an officer in the Carabinieri, or military police.

During the 1980s he studied business at Milan’s Bocconi university, joined McKinsey, the consulting firm, and then went to Harvard.

When he returned to McKinsey in 1991, one client was to have a lasting impact on Mr Colao – Omnitel, Italy’s second-biggest mobile phone operator.

Having helped devise Omnitel’s original business plan, Mr Colao joined the company as chief operating officer in 1996 and three years later was made chief executive.

One former Omnitel executive says: “The company was a big start-up, growing very fast. The challenge was to build up a service that was better than Telecom Italia.”

In 2000, Vodafone acquired Omnitel as part of its takeover of Mannesmann, the German telecommunications company. Mr Colao subsequently took responsibility for Vodafone’s southern European operations.

Today, Mr Colao has the most arduous job at Vodafone after Mr Sarin. Running the group’s European operations is difficult because they can no longer report rapid growth simply by putting mobiles into people’s hands for the first time. The markets are saturated with mobiles.

Mr Colao is implementing Mr Sarin’s strategy of increasing revenue partly by encouraging customers to use their mobile phones for internet services such as e-mail.

In the six months to September 30, Vodafone’s European operations reported revenue growth of 2.3 per cent compared with the same period last year.

Earnings before interest, tax, depreciation and amortisation fell 1.5 per cent, but some analysts regard that as a solid performance given Vodafone ran up higher costs by poaching customers in its four core European markets. Significantly, operating expenses were kept flat.

Nick Delfas, analyst at Morgan Stanley, who has a “sell” rating on Vodafone, says: “The results in Europe in the last six months were excellent.”

If Mr Colao can keep up that momentum, this low-key operator may soon have a far more prominent role at Vodafone.