English rugby was rocked by a new crisis last night as the 12 Premiership One clubs announced that they will not compete in next season's Heineken Cup and European Conference competitions.

The decision was announced by English First Division Rugby (EFDR) following a meeting in London of the 12 top clubs' owners and backers.

The move is a clear protest vote at the existing domestic season structure, which clubs claim does not give them sufficient opportunities to generate revenue.

The announcement will come as a serious setback to tournament organisers. The European Cup is in its third season and reaches a climax in three weeks' time when Bath take on holders Brive in the final in Bordeaux.

Next season's competition format sees the pool stages played in a six-week block between early October and mid-November, meaning an effective shutdown of the League programme, which has incensed the wealthy club benefactors.

A prepared statement from EFDR read: "European rugby was felt to be hugely important for the future of the game, but the existing structure often worked to the detriment of domestic league rugby.

"It was therefore decided, as from next season, not to participate in the existing ERC competitions in order to create a better structure.