The mobile phone group Vodafone was one of the biggest losers on the London stock market on Wednesday.

The firm's shares fell 6%, and because it is the UK's fourth biggest quoted company, that fall has had a big effect on the FTSE 100 index of blue-chip shares.

It's simply an excuse to knock the shares; there's no substance to the rumours

John Tysoe WestLB Panmure

At one point Vodafone stock fell to 79.75 pence, its lowest level since December 1997.

Concerns about the string of accounting scandals affecting companies such as Enron, WorldCom and Xerox have unsettled the markets.

And market rumours were suggesting that companies in the telecoms sector could be next.

Market concerns dismissed

But Vodafone said concerns about its accounts were completely unfounded.

"I can categorically confirm that there is no basis for any of these rumours," a Vodafone spokesman said.

Analysts also dismissed the market concerns about Vodafone's accounting practices.

"It's simply an excuse to knock the shares; there's no substance to the rumours," said John Tysoe from WestLB Panmure.

Investors were also worried that Vodafone would be downgraded by credit rating agencies.

That would mean that Vodafone was being seen as a higher risk company and it would cost the business more to pay off its debts.

Vodafone's shares ended the day at 80.5p