Championship clubs are considering forming a breakaway league and introducing a salary cap which could threaten relegated Saracens’ attempts to keep hold of England stars such as Owen Farrell and Maro Itoje next season, the Guardian understands.

Other options being explored by club owners, who are raging at the Rugby Football Union’s decision to slash their funding by 50%, include organising mass protests at England’s forthcoming Six Nations matches at Twickenham and calling for the return of the promotion playoffs.

Bill Sweeney, the RFU chief executive, has also come in for stinging criticism as the angry fallout continued on Wednesday. One club owner described Sweeney, who took over from Nigel Melville last May, as a “hatchet man” and the union as “deplorable”, while Will Stuart, currently part of Eddie Jones’s England squad, called the cuts “pure garbage” on social media.

It is understood a breakaway league was suggested on Tuesday, when the clubs were informed of the cuts, with a proposal to buy the league from the RFU for a nominal fee. The clubs are concerned that while the RFU has confirmed funding will be halved for next season, they will not receive a penny from the 2021-22 campaign and as a result see no reason to remain under control of the union. Some clubs are also believed to be exploring the possibility of joining the Pro14.

Any changes to the Championship’s structure would have to be agreed by all 12 clubs, whose chairmen struck a defiant tone on Wednesday against what they perceive to be “handing the Premiership ring-fencing on a plate”. One believes supporters at England’s Six Nations matches against Ireland and Wales should protest against the RFU’s decision while it is understood a £2.5m salary cap has also been suggested. With Saracens in breach of the Premiership’s £7m salary cap this season, keeping hold of their top earners would be almost impossible.

Within the Championship there remains a sense of astonishment at the timing of the cuts, which will lead to hundreds of job losses, and a feeling that the RFU’s explanation does not stand scrutiny. It is understood the Championship clubs were offered a three-year extension to their funding last year, with a modest increase, if they agreed to a ring-fenced Premiership. The offer was rejected and next season’s cuts have been described by one well-placed source as “tit for tat”.

Sweeney is taking the brunt of the criticism along with Conor O’Shea, who started as the RFU’s director of performance rugby last month. The Jersey Reds chairman, Mark Morgan, called the cuts “immoral and irresponsible”, adding: “With Bill Sweeney’s heralded business background, this is astonishingly poor execution.”

Cornish Pirates and Coventry released a joint statement which read: “For the RFU to use their own failure to deliver as a justification for unilaterally decimating the Championship is nothing short of outrageous, not least because it has come from people – Bill Sweeney and Conor O’Shea – who have been in post for only a short time.”