The US has passed a bill to protect American writers and authors from “libel tourism” in British courts by decreeing that foreign libel judgments are not enforceable in the United States.

The move came after years of bewilderment with what are regarded as draconian UK libel laws that saw a string of cases being heard which would never have been brought in the US.

Many involved celebrities or foreigners suing American publications and books whose content was viewed by a relatively small number of people in Britain.

Supporters of the Securing the Protection of our Enduring and Established Constitutional Heritage (Speech) Act said “libel tourism”, in which plaintiffs shopped around for countries with tough libel laws, undermined the cherished first amendment of the US constitution that guarantees free speech rights.

The legislation will prevent US federal courts from recognising or enforcing a foreign judgment for defamation that is inconsistent with the first amendment and will bar foreign parties from targeting the American assets of an American author, journalist, or publisher as part of any damages.

Campaigners for more liberal libel law in Britain said they hoped the new law would influence the Government as it prepares a draft reform bill for publication in January.

Padraig Reidy, a spokesman for the Index on Censorship, said: “It’s a vindication of our argument that English libel laws in their current state do not encourage or protect free expression. The fact that Britain’s best ally feels the need to protect itself from the English libel courts demonstrates the need for reform.”

Steve Cohen, a Tennessee Congressman who drafted the bill, said it was vital that Americans’ “rights are never undermined by foreign judgments.”

The bill had such widespread support from Democrats and Republicans that it was passed on a voice vote in Congress.

Arnold Schwarzenegger, the former actor and California governor, was among the first “libel tourists” to use the British courts when he sued the author Wendy Leigh for alleging in an unauthorised biography that he held pro-Nazi views earlier in life.

Cameron Diaz sued the tabloid National Enquirer for wrongly alleging she was unfaithful with a married man, while Don King, the boxing promoter, sued a New York lawyer who had provided an online answer to a California website suggesting that King was anti-Semitic.

Another case involved a Greek citizen who sued the New York Times and International Herald Tribune, which both have minimal distribution in Britain, arguing the newspapers had claimed he spread false rumours which may have resulted in the break up of the Beatles. The Cyprus defence minister used the London libel courts to sue against a Cypriot publication.

However the case that provided the momentum for the change in American law was that of New York-based academic Rachel Ehrenfeld.

In 2004, she was sued in London by Khalid bin Mahmouz, a Saudi billionaire she accused of financing terrorism in a book, Funding Evil, that drew on statements made by the Federal Reserve Board and a report by a US senate committee.

The court decided to hear the case even though only 23 copies had been purchased online through Amazon in Britain, and awarded damages of $225,000 (£150,000) against Ehrenfeld.

Mahmouz did not pursue her assets in the US – she had none in Britain – but the author started a campaign to protect people in her position. That led to a law being declared in the state of New York that served as the model for the Speech Act.