British software tycoon Mike Lynch launched an attack on the overreach of U.S. prosecutors around the world as he kicked off his fight to prevent extradition to America.

The Department of Justice is “not the global marshal of the corporate world,” his lawyer, Alex Bailin, told a London court Tuesday. British executives should face allegations of misconduct at home, Bailin said, noting that the U.K.’s Serious Fraud Office may reopen its own investigation into alleged fraud at Lynch’s software company, Autonomy.

The U.S. “is not an overweening international police force,” Bailin said.

Both Hewlett Packard Enterprise Co. and the DOJ have pursued Lynch and his deputy over allegations that Lynch dressed Autonomy up for a sale to HP by inflating sales. The Silicon Valley hardware giant acquired Autonomy for $11 billion in 2011 only to write down the value by $8.8 billion a year later.

The high-profile case has attracted significant political attention with lawmakers highlighting perceived imbalances in the U.S.-U.K. extradition treaty. Lynch argues that a “very substantial measure” of the supposed wrongdoing took place in the U.K.

Lynch is also waiting for the verdict in a $5 billion London civil trial brought by HP. Judge Michael Snow has agreed to wait for the outcome of that trial before making his own decision in the extradition case, Bailin said.