VICTIMS of Brazil’s worst environmental disaster launched their £36 billion class action lawsuit against a “cynical” global mining giant at the High Court today.

The Mariana dam disaster unleashed a torrent of toxic waste that  killed 19 people and devastated local communities on November 5 2015.

More than 600,000 Brazilians, 46 local governments and about 2,000 businesses are suing Australia-based global mining giant BH over the collapse, which studies say destroyed two villages, killed 14 tons of freshwater fish and damaged 410 miles of the Doce river.

The watercourse, which the Krenak indigenous people revere as a deity, was polluted so badly that it has yet to recover.

Law firm Pogust Goodhead, representing the claimants, said the lawsuit would seek the largest-ever environmental payout.

The case entered a decisive stage today, with the beginning of a 12-week trial to determine whether BHP is liable.

The trial comes days after BHP announced that the company and its partner in Samarco, Vale SA, were negotiating a multibillion-pound settlement with Brazilian public authorities covering the damage to people, communities and the environment.

The potential settlement will have no impact on the London case, Pogust Goodhead said.

BHP argues it did not own or operate the dam, which held mining waste known as tailings.

However, it is said to own 50 per cent of Samarco, the Brazilian company that operates the iron ore mine where the tailings dam ruptured.

According to BHP, a Brazilian subsidiary of its Australian holding company was a 50 per cent shareholder in Samarco, which operated independently.

The claimaints’ lawyer Alain Choo Choy argued that the action of BHP in fighting the case and funding separate litigation in Brazil showed that the mining company was “cynically and doggedly trying to avoid” responsibility for the dam collapse.

“Although that is BHP’s choice, it cannot properly now claim to be a company ‘doing the right thing’ by the victims of the disaster,” he added in court filings.

The case was filed in Britain because one of BHP’s two main legal entities was based in London at the time.

“BHP will continue to defend the [British] action, which it believes is unnecessary because it duplicates matters already covered by the ongoing reparation work and legal proceedings in Brazil,” BHP said on Saturday.