On Friday, British prosecutors charged the three cricketers and sports agent Mazhar Majeed with taking bribes and ordered them to appear at London's City of Westminster Magistrates Court on March 17.
Butt, Amir and Asif, who have denied any wrongdoing, were suspended by the ICC in September under its anti-corruption code, which provides for a maximum life ban for the offence of spot-fixing.
The announcement by Britain's Crown Prosecution Service came on the eve of the three-man tribunal's scheduled verdict.
The members of the tribunal considered the case for six days last month following allegations in a British newspaper that the trio had arranged for deliberate no-balls to be delivered in the fourth test at Lord's last year.