The mobile phone giant Vodafone has made a loss of �13.5bn, the biggest loss in UK corporate history.

It means the company was, in effect, losing �428 a second in the 12 months to the end of March.

Vodafone wrote off �6bn because the value of some of its investments had fallen during the telecoms boom-and-bust cycle.

We have outperformed... this should be a matter of rejoicing

Sir Christopher Gent chief executive

But it did not write down the value of the German company Mannesmann for which it paid �112bn at the height of the telecoms boom.

The chief executive, Sir Christopher Gent, told BBC News there was no reason to write down the value of its Mannesmann assets.

"They certainly have this year delivered tremendous growth and we expect them to continue to deliver very good growth in the future," he said.

Show of strength

Overall, the company wrote off a total of nearly �20bn, including other accounting charges.

Biggest UK losses

Vodafone �13.5bn Marconi �5.7bn Cable & Wireless �4.7bn Corus �1.14bn 3i �960m Railtrack �534m BA �200m

But its operating profit in the year to the end of March increased by 35% to �7bn, a higher figure than had been predicted.

"Not only have we produced better operating profits and lower debt levels than anyone expected," said Sir Christopher.

"We've also produced �2.4bn of free cash which shows you how strong we are in terms of trading."

Outperformed

Sir Christopher is facing protests from shareholders over bonus payments related to the Mannesmann deal.

Sir Christopher Gent faces protests over bonus

He was awarded a �10m bonus two years ago, with half paid immediately in cash, and the second half due to be paid in shares in July.

"The fact is that we have outperformed all of the guidance we gave to shareholders when we did the Mannesmann transaction and this should be a matter of rejoicing," he said, defending his bonus.

"We've got a British company achieving these kinds of results and this kind of progress.

"I'm a shareholder too, a major shareholder, all of my wealth is in this company and we haven't misperformed," he added.

Bonus contention

The National Association of Pension Funds (NAPF) told BBC News Online that it disapproved of a bonus being paid simply for completing the Mannesmann transaction.

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Spokesman Andy Fleming said: "The rewards should reflect improvements in shareholder value".

Since the second part of the bonus package had already been approved, Mr Fleming thought it would be paid as planned.

But he said NAPF members might choose to register their disapproval of Vodafone's bonus system by voting against this year's remuneration package at the annual meeting in July.

The company has not yet given any details of its latest bonus plans.

Shares rise

Chris Godsmark, a telecoms analyst from Investec, said Vodafone's �6bn write-down reflected only its peripheral businesses.

He said it was clear Vodafone believed that in the longer term the amount it paid for Mannesmann would be justified because of all the new products and services that would come through in mobile.

"We're all waiting to see what those new products and services will be and how quickly they'll roll out," he said.

Vodafone's shares opened five pence higher at 112p, making up ground they had lost on Monday.

Vodafone, like other telecoms companies, has seen its share price fall sharply because of slower subscriber growth and doubts over the money-spinning potential of the next generation of mobile phones.

Earlier this month, the shares fell to 92.5p, their lowest level for more than two years.

At their height, in March 2000, they were worth 399p.