A top judge has slammed Wirral Council for a planning blunder that could have led to hundreds of weddings being cancelled.

The local authority has been blasted for “unlawfully” attempting to conceal a mistake that saw it grant planning consent for wedding marquees at Thornton Manor Estate.

The venue has kept the marquees in place and continued to host weddings prior to the case being brought as high up in UK law as the Court of Appeal, where judge Lord Justice Keith Lindblom described the council’s actions as the “antithesis of good administration.”

Owners Thornton Holdings Limited applied for planning permission back in 2010, which was granted for just five years by the council’s committee, the judge said.

But when the formal planning consent was sent out, it had no such conditions attached to it, and the venue has kept the structures in place until now, despite originally only being given consent for five years.

The case went to the High Court last year after the owners of nearby Thornton Hall Hotel, which runs a competing wedding business, mounted a legal challenge to the permission.

At the High Court, a judge overturned planning permission for the three marquees in the grounds of the 19th century manor after the council admitted to having incorrectly given them permission to be erected indefinitely.

According to the Planning Resource, that ruling was then challenged by Thornton Holdings, so the case went to the Court of Appeal.

A year ago, it was reported hundreds of weddings at the venue could be cancelled – with it having accepted bookings until 2020 – expecting more than 50,000 guests between March 2018 and 2020.

Despite that, the marquees remain in place at the beauty spot “to this day”, with weddings continuing to take place.

When contacted by the Local Democracy Reporting Service, a spokesman for Thornton Manor said the council had invited it to apply for renewed permission, which officials are now in the process of doing.

He added: “No weddings are having to be cancelled and Thornton Manor are continuing to operate business as usual.”

Criticising the council last week, Lord Justice Lindblom said even after noticing the “indisputable error”, the authority proceeded to act “unlawfully” and conceal it.

He added: “[The council] initially attempted to put matters right by generating a fictitious decision notice and manipulating the planning register.

“Whether its intention was to reverse its error or to obscure it, the effect of the action it took was only to disguise what it had in fact done.”

Speaking on Wednesday, a Wirral Council spokesman said the authority “note and accept” the judge’s ruling.

A statement said: “As the local planning authority, we had already acknowledged our administrative failing in this case and as such chose not to contest the judicial review. We note and accept the judge’s ruling.”

Lord Justice Lindblom also acknowledged last week that the delay in the case reaching court was “extreme”.

But he added: “There can be no doubt that the circumstances of this case, viewed as a whole, are extremely unusual. We would go further; they are unique.”

He also said following the council finding out about its error, it could have revoked the permission, or issued a discontinuance order, but had shown “no inclination” to follow either course, both of which could have given rise to a claim for compensation by Thornton Holdings.

Another “highly abnormal” aspect of the case, he said, was that the council had “actively supported” the challenge to the planning permission.

But the judge said Thornton Holdings “were well aware from the outset that the planning permission had been wrongly issued, and knew precisely what the council’s error had been”.

It had only sought to rely on the 2011 consent when the council began to press for the marquees’ removal.

He added: “We cannot accept that Thornton Holdings have suffered any material hardship or prejudice as a result of the delay in the claim being issued. If anything, the delay worked in their favour, in the sense that it enabled them to take advantage of an unrestricted grant of planning permission that they knew the council had never resolved to grant.”

Dismissing the appeal, the judge said: “This is clearly a case in which the interests of good administration, and indeed the credibility of the planning system, weighed compellingly in favour of the court having the opportunity to hear the claim and, if the claim succeeded, to deal with the council’s error.

“If, as the council has readily acknowledged, the decision notice it issued was issued without lawful authority, it might fairly be described as the antithesis of good administration.”