Supporters of rival super-casino bids were engaged in a furious war of words today after business leaders vowed to press ahead with a controversial ballot.

Birmingham Chamber of Commerce is to poll members of its governing council to discover whether they back plans for a casino at the NEC or Birmingham City Football Club's proposed stadium complex in Saltley. But it has ruled that anyone who fails to vote will be counted as backing the NEC proposal - because that is the preferred option of the Chamber's policy director Jerry Blackett.

The ballot provoked an angry reaction from Blues' managing director Karren Brady, who accused the Chamber of vote-rigging.

But last night the Chamber said it would press ahead with the poll.

Birmingham City Council is still deciding whether to support plans for a £340 million casino at the new Blues ground, while Solihull Council has already come out in favour of a £250 million proposal at the NEC. The Government is to issue a licence for only one regional casino in Britain. A panel will consider bids from across the country, with Ministers making the final decision.

Birmingham Chamber of Commerce has sent ballot forms to the 99 members of its governing council inviting them to express a preference for either the NEC or the Birmingham City bids, along with a letter from Mr Blackett which explains why he favours theNEC proposals. The Chamber insists the poll could go either way, but admitted it would count any abstentions as votes in favour of the NEC.

A spokesman said: "This is to encourage people to vote, and shouldn't affect the final result because we don't expect to get many abstentions."

Mr Blackett said: "After listening to the arguments from both sides at an earlier Chamber council meeting, I recommended support for the NEC bid.

"The notes from the council meeting on which the recommendation was based were verified as a true and fair record by each side at our request."

He said a study commissioned by Birmingham City Council to examine the rival bids was unlikely to report back before the March 31 deadline.

Ms Brady has written to Mr Blackett accusing him of trying to "skewing" the result of the vote.

She said she expressed "absolute indignation and profound disappointment with you personally and the Birmingham Chamber of Commerce for its inability to conduct a fair and representative process on behalf of its member organisations and the city it represents."

She added: "It is very disappointing that the Birmingham Chamber of Commerce is recommending that its members support a Solihull proposal over a proposal in the heart of Birmingham."

Ms Brady called for the ballot to be re-run, but the demand was rejected by the Chamber last night.

Ken Hardeman, Birmingham City Council's cabinet member for regeneration, and a supporter of the Blues' proposal, said: "To rule that anyone not voting will count as support for the NEC bid is thor-oughly unfair."

The football club's planned supercasino would be part of an all-purpose stadium on 60 acres of contaminated land at Saltley, designed to create 6,000 new jobs.

But the Chamber's letter to its council members says the NEC proposal would bring "huge benefits" in the shape of a £650 million income flow over ten years.

Speaking in the House of Commons yesterday, Culture Minister Richard Caborn said the Government wanted to build a number of regional casinos - but had agreed to build only one because of Conservative objections.