Proposals to move the English Premiership final from the end of the season and to play European club rugby in a single block from March to June are among the ideas being considered by the leading English club owners as they prepare to thrash out the detail of a new tournament to replace the existing union-run Heineken Cup.

They are also keen to re-emphasise that Irish, Welsh, Scottish and Italian sides are all welcome to join the new Anglo-French-driven competition, heading off complaints from the Celtic unions that the loss of Heineken Cup rugby would be a calamitous blow to the sport in their countries. The Premiership club backers and chairmen, who are due to meet on Wednesday, are understood to be happy for all the six nations to be represented.

What may change at some stage is the structure of the season, previously hard to amend when European Rugby Cup Ltd controlled the Heineken Cup schedule.

Under a new regime there might be scope for the Premiership to be played in its entirety between September and early February. That, in turn, would leave the way clear for a “new” Heineken Cup to be staged between March and June, possibly even involving provincial sides from South Africa from 2015-16 onwards.

"Potentially the Premiership final could be before the Six Nations, " a Premiership insider told the Guardian. "Then, if you ran a new Heineken Cup with the South Africans involved between March and June, that would be a pretty good competition for four months. You'll hear people not just talking about a new European Cup but a new trans-border competition."

The clubs, emboldened by the extra cash available from their €180 million television rights deal with BT Sport and having given notice of their intention to withdraw from the existing ERC-run Heineken Cup at the end of the season, are adamant their plans will not be stymied by national unions or the International Rugby Board.

A senior English club figure said: “There are still some people who will say: ‘You can’t have a cross-border competition without the permission of the French Federation, the RFU and the IRB.’ Those people are living in the past.

“What has changed the whole landscape is the BT Sport deal because suddenly the clubs have got their own broadcaster and are bringing their own money into the game. The French will also be selling their equivalent TV rights shortly. The unions can huff and puff as much as they like but the reality is that the unions are not going to stop a competition bringing in £30m to £40m to rugby.”

There is also a widespread view that the Welsh, Scots and Irish cannot afford not to be part of any new competition, even if it is club-run.

"My guess is that next year there will be a European competition with all those sides involved and it could even be called the Heineken Cup," the source predicted. "The English and French clubs will play together next year and the Scots, Welsh, Irish and Italians are welcome to join us." Guardian Service