LONDON—The Super League collapsed before a ball was kicked in the European breakaway competition after being abandoned by the six English clubs, leaving the Spanish and Italian participants stranded. Arsenal, Chelsea, Liverpool, Manchester United, Manchester City, and Tottenham throughout Tuesday evening deserted the proposal to launch a largely-closed midweek competition amid an escalating backlash from their supporters and warnings from the British government that legislation could be introduced to thwart it. The Super League project was overseen by Real Madrid President Florentino Perez, who also signed up Barcelona and Atlético Madrid in Spain, and Juventus, AC Milan, and Inter Milan from Italy. The rival for the UEFA-run Champions League became unviable without the six clubs from the world’s richest league. The remaining fledgling Super League organization was defiant, blaming “pressure” being applied for forcing out the English clubs and insisting the proposal complied with the law and could yet be …