Councillors will have to re-think the reason they refused major work to Butterley Spillway.

And it’s because their original concerns over the historic Marsden landmark may not stand up at a planning inquiry which is set for January.

Kirklees councillors unanimously kicked out Yorkshire Water’s £6m plan to replace the existing stone spillway at Marsden with concrete sections.

They ruled that the “proposed works, by reason of their scale, design and the materials of construction would be incongruous and disharmonious with its surroundings which would have a detrimental impact upon the visual appearance and setting of the landscape and the listed building” contrary to parts of the National Planning Policy Framework (NPPF).

However, following new evidence submitted by Yorkshire Water, the council’s own landscape architect has said he cannot disagree with large parts of Yorkshire Water’s landscape and visual assessment.

They believe it will be difficult to substantiate the original argument, so on Thursday councillors will be asked to re-think the reason for their refusal.

Planning officers have asked they amend the refusal to say that the “proposed works by reason of their scale, design and the materials of construction would result in substantial harm to the significance and setting of the heritage asset” contrary to a section of the NPPF.

It is possible that Kirklees Council may now be liable for some costs for “time wasted by their (Yorkshire Water’s) witness in preparing their case on the basis of the original reason for refusal”, although that is yet to be determined.

A Planning Inquiry is set for January 20 and both sides are busy preparing their case for the Planning Inspector to consider.

Councillors were unanimous in their view that the work proposed by Yorkshire Water will spoil the Grade II listed Spillway.

The plan would involve replacing some masonry on the base of the spillway with reinforced concrete, with other works to the cascade and a masonry and concrete wall.

A huge campaign has been waged to keep the original spillway, with supporters getting backing from many influential bodies.