Watson said Labour would press bookmakers to pay a compulsary levy to fund research and NHS treatment for problem gamblers, promising to end the “destructive cycle of addiction”.
“I can tell you that a Labour government will introduce a compulsory levy,” Watson said in hes speech.
“We now know that when vulnerable people try to opt out of online gambling, companies don’t always block their accounts as they should,” he said.
“Gambling companies are even harvesting data to deliberately target low-income gamblers and people who have given up.”
Earlier this month, Watson also put pressure on the government of Theresa May renewing his anti-gambling campaign as he proposed to ban betting firms from advertising on football shirts.