IVS was to collect the proxy cards yesterday and transport them back to its facilities in Delaware, where 25 staff would begin the tedious semi-automated process of counting the votes.

Hewlett-Packard chief executive Ms Carly Fiorina last night claimed shareholder backing for the company's controversial $21 billion (€23.8 billion) bid for Compaq Computer. She would not provide details on the preliminary margin of victory, other than to say that it was quite "slim but sufficient".

It would take "several weeks" for the final result to be known, she added.

In a statement following a special meeting of more than 1,000 Hewlett-Packard shareholders, Ms Fiorina said: "We are gratified that Hewlett-Packard shareowners recognise the compelling strategic and economic benefits of the merger and that a decisive majority of shares not affiliated with the Hewlett and Packard families and foundations appear to have been voted in favour of this transaction."

But even as polling closed, sources suggested early returns indicated the vote was so close that neither side could be certain of victory implying that the margin would be within three percentage points.

Mr Michael Barbera, one of three partners of IVS Associates, which is counting the votes, said it would probably take several weeks to release final results.

Because shareholders are allowed to vote more than once, IVS must file all proxies by hand in order to ensure that only the last vote cast by each shareholder is counted.

Once voting cards are filed, information on valid proxies is keyed into a computer, which tabulates the vote.

Neither Hewlett-Packard nor the Hewlett camp would be present during this process, but they would have to review and possibly challenge results. IVS would then issue a ruling on the challenge and the vote would then be finalised.

While proxy voting is generally clean and transparent, Mr Barbera said that results could swing as much as 3-5 per cent following a review. That would mean that neither side could be sure of the results if the margin of victory was less than 3-5 per cent. "If it's close, really close, we're not going to know for sure," he said.

An additional 1,000 or so shareholders were expected to cast their votes by hand yesterday, but their impact would be minimal. Hewlett-Packard's 900,000 shareowners hold about 1.95 billion shares.

At yesterday's meeting, Ms Fiorina was booed three times while defending her plan to acquire Compaq. In contrast, Mr Walter Hewlett, the dissident Hewlett-Packard director spearheading opposition to the deal, received two standing ovations as he thanked employees for not becoming distracted by the debate over the merger.

Boos aside, the meeting was a remarkably polite affair, in stark contrast to the vicious exchanges during a five-month proxy battle. A weary-looking Ms Fiorina fielded questions from employees, retirees and shareholders.

Mr Hewlett, who has organised, bankrolled and starred in an aggressive campaign to derail the Compaq deal, said he had tried to shine a "bright light" on the details of the merger so that shareholders had as much information as possible when they voted.

The two sides have spent tens of millions of dollars in a bitter proxy battle during which they swamped shareholders with advertisements, mass mailings, faxes and even phone calls.

Hewlett-Packard says the deal will transform it into a computer giant capable of providing the end-to-end products and services to rival industry leader IBM.

Mr Hewlett, son of one of the company's co-founders, argues the transaction is inherently risky and takes the company in the wrong strategic direction.

Compaq shareholders are expected to second the apparent decision to back the deal when they vote today.

Hewlett-Packard shares fell 26 US cents to $18.99, as the company claimed victory, reversing earlier gains, while Compaq added 69 US cents to $11.05, also reversing its earlier course.