The Court of Appeal in Brussels on Friday (23 October) upheld the decision of the Belgian Competition Authority (BCA) enabling the 2016 launch of the league, which organisers claim will “revolutionise” showjumping.
The competition will be run each Friday at GCT shows — which will take place in 15 cities next year.
It was intended to boost prize money to around €20m (£15.6m).
Club owners would field “star strikers” and two riders from a squad of four would be selected to compete at each event.
In June, the GCL filed a complaint with the BCA alleging the FEI had breached EU competition law by using its rules to prevent riders and horses from competing in events not approved by the FEI by imposing a so-called “exclusivity clause”.
In July the BGA said the GCL could go ahead in 2016, however this was challenged by the FEI.
Now the Court of Appeal said the FEI had failed to demonstrate the injunction “inflicted serious and irreparable harm” on the federation.
The court said the FEI had managed for more than a century without the clause and failed to show why it was indispensable.
“Momentum around the GCL concept has been rapidly gathering pace since it was conceived and we welcome the news that the last hurdle has been removed,” said Frank H McCourt Jr, co-owner of GCT.
“We now look forward to focusing our energies on building a new and exciting era for showjumping.”
The FEI told H&H it is “awaiting the written decision on interim measures” following the judgement.
“The FEI’s appeal on the merits of the interim measures decision will now continue before the Court of Appeal,” added a spokesman.
“We will use all legal means to defend the case.”
All vets, riders and FEI officials would now be able to take part in the series “without repercussions” said the GCL.
The GCL said it is committed to “improving standards for horses, riders, owners and sponsors in the sport and horse welfare will remain a top priority”.
It has invited the FEI to oversee horse welfare safeguards at the new-format competitions by inviting FEI officials to join its own top-class team of vets.
But an FEI spokesman told H&H: “Unsanctioned events are not subject to FEI regulations, and their organisers and participants are not accountable to the FEI for compliance with these regulations.
“As a result, the FEI has no way of safeguarding the welfare of horses and athletes participating in unsanctioned events, or of protecting the integrity of the events.”