LaLiga's deal with CVC Capital Partners has been labelled "totally illegal" by the Spanish Football Federation (RFEF).

The €2.7billion (£2.3bn) arrangement that was announced last week would see private equity firm CVC acquire 10 per cent of the league's commercial business.

The other 90 per cent of the investment was earmarked to boost cash-strapped clubs in the top two tiers of Spanish football amid the coronavirus pandemic.

However, the deal – which must be approved by two thirds of the 42 clubs involved at Thursday's general assembly – was heavily criticised by Real Madrid and Barcelona.

Madrid and Barca allege the agreement affects all clubs' audiovisual rights for the next 50 years, with Los Blancos threatening to take legal action against LaLiga and president Javier Tebas as they were not properly consulted.

In a long statement released on their official website on Wednesday, the RFEF said it is also totally opposed to the proposal that has been put forward.

The statement read: "This operation, carried out with the absence of the slightest publicity and concurrence in the selection of the successful bidder, has two parts. The one related to the commercialisation of audiovisual rights, on the one hand; and the rest of the LNFP businesses, which make up a heterogeneous group, on the other.

"Regarding the agreements between the LNFP and CVC related to the audiovisual rights of sports clubs and corporations, the RFEF must express its opposition. 

"Not only for legal reasons, which will undoubtedly generate numerous litigation derived from the agreement and may put its own viability in doubt, since it is intended to force some legal institutions to the extreme; but also for economic reasons, since the rights of clubs and SADs are heavily taxed for the next fifty years in exchange for a small amount of money. 

"But the most important thing is that the agreement increases inequality and, in a capital and definitive way, makes a reasonable evolution of the format of professional football competition in Spain impossible. 

"Causing that in practice and in application of the agreement the competition is petrified without the possibility of evolution or can only be modified when a third party outside the sports structure so decides or agrees, a fact that flagrantly violates the law and the European sports model. 

"In addition, forget about the clubs that play non-professional competitions that, at the time of their promotion to professional competition, will see that their income is reduced by CVC's remuneration, without having obtained any benefit from the contribution of that entity."

The RFEF also claims the agreement with CVC does not account for the clubs who will be promoted to LaLiga further down the line, which would see their income reduced if not paid upfront.

"If there are clubs who, with their own rights, wish to indebt themselves voluntarily, they are free to do so, whether at market rates or extortionate ones, but not through a totally illegal agreement which obliges everyone else, via a false attribution on the part of the LNFP of rights it does not own," the statement continued.

"We consider this attempt to bypass the law and create an agreement which is economically dreadful and deplorable in terms of the future of Spanish football while, in contrast, excellent for an investment fund and other possible beneficiaries.

"The RFEF must also warn that it will not allow during these 50 years any reduction in the contribution from audio-visual rights given to the lower tiers of football."