The governing body of England's top rugby union clubs has given notice of its intention to pull out of the Heineken Cup and Amlin Challenge Cup.
The move comes amid disagreements over how the competitions are organised.
French clubs have also threatened to withdraw, but as two years' notice has to be given the move is perceived as an attempt to force others to negotiate.
"We hope that there will now be an urgent dialogue," said Premiership Rugby chief executive Mark McCafferty.
McCafferty added that he hopes discussions can commence soon regarding "the future of European cup rugby, including qualification, competition formats and ambition to expand into new markets".
The governing body's notice period extends to the end of the 2013-14 event, at which point they say they will exit the competitions.
Meanwhile, Keith Earls will have to sit out the second Test against New Zealand in Christchurch on Saturday with a pectoral muscle injury.
The Ireland utility back suffered the injury near the end of the 42-10 defeat in Auckland.
Medical staff will now attempt to get Earls fit and raring to go for the third Test on June 23.
Connacht full-back Gavin Duffy has been called up as cover.