Hundreds of bus workers are to stage an all-out strike in a dispute over pay.
Members of Unite employed by Stagecoach Merseyside held an initial day of strike action on Monday.
The union said Stagecoach had failed to make an improved pay offer so its members will take all-out, continuous strike action from Wednesday July 20.
Prior to this, there will be one-day strikes on Friday July 15 and Monday July 18.
Unite general secretary Sharon Graham said: “Stagecoach is a wealthy company, it can easily afford to pay fairly and Unite is determined to ensure that it does.
“Our members simply want the rate for the job and are not going to accept being underpaid a moment longer.
“Stagecoach’s refusal to make an offer that would resolve this dispute has, however, resulted in an escalation in industrial action.
“Unite will be giving our members the union’s complete support until they receive an acceptable pay increase.”