The chairman of British betting company Sportingbet, Peter Dicks, was detained by American authorities in the early hours of today in what is being seen as a further crackdown on online gambling.

Mr Dicks is being held at JFK Airport by the Police Department of the Port Authority of New York and New Jersey after a warrant was issued by the Louisiana State Police. Police sources said that the charges related to Louisiana’s strict laws on gambling by computer but that no Federal charges were involved.

The Port Authority confirmed his detention with a spokesperson saying: "We were acting as the middle man. We were informed that Mr Dicks was wanted on an out-of-state warrant." Mr Dicks was expected to be extradited to Louisiana to face charges.

The detention of Mr Dicks, 64, comes just two months after David Carruthers, the chief executive of BetOnSports was arrested in Texas on alleged fraud and racketeering charges. Mr Carruthers, who has maintained his innocence, was on his way to the company's offices in Costa Rica.

Mr Dicks was detained while travelling to the country on non-company business. A spokesman for Sportingbet could not confirm whether he had been arrested or charges levelled.

He faces a US hearing at 2pm London and 9am Eastern time.

But the City immediately took fright and marked online gaming companies' shares down heavily.

PartyGaming, which today posted a 47 per cent increase in first-half profits to $380 million, fell as much as 11 per cent. It was trading later down 8.74 per cent at 107p.

And World Gaming, which revealed today that it was in talks to be taken over by Sportingbet in a deal worth £57.6 million, crashed more than 28 per cent to just 66p. Sportingbet has been considering an offer of 104p a share for the company.

888 Holdings tumbled more than 12 per cent to 149.25p.

Sportingbet asked for its shares to be suspended "pending clarification of the situation". The shares were suspended at 239p, down 2.05 per cent since the open.

At this price Sportingbet is worth more than £1 billion.

BetOnSports dismissed Mr Carruthers in the wake of his arrest and the charges. It has shut the office in Costa Rica and culled its staff.

Confidence in internet gambling operators has taken a serious knocking since the arrest of Mr Carruthers with some regulators in America determined to outlaw online activities.

Sports betting is currently deemed illegal by US residents, while A Bill has been passed by the House of Representatives that, if approved later by the Senate, would tighten the laws across the board on betting in the US.

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