Mobile phone giant Vodafone may be forced to slash the value of recent acquisitions by billions of pounds.

Chairman Sir Chris Gent is expected to admit the group spent too much on deals at the time of the technology boom when it reports annual results next month.

Japan's NT&T wrote down £7 billion from the value of its overseas investments last week and City investors are nervous Vodafone may have to follow suit.

The move, while not hurting the operational performance of the group, could lead to record bottom-line losses.