The 8ft-long platform at Footmeadow in St James – installed as part of a £1.6m revamp of three town parks – means full-length canal boats have great difficulty turning around on the Westbridge arm of the river, which is blocked off to boats past the bridge.

Only two boating enthusiasts competed in the Westbridge Challenge over the May Day Bank Holiday, even though the annual boating contest which uses the stretch of water has attracted up to 40 boats in the past.

Lynda Payton, of the Northampton branch of the Inland Waterways Association, said the unusually low turnout may not only have been because of the fishing platform, but said it was proving a problem for full-length boats.

She said: "It's a bit of a silly place to put it. It does cause a little bit of a problem to the larger boats. What will probably happen is it will be struck by boats and damaged."

Steve Winder, chairman of the St James Residents' Association, said the installation of the platform had not been properly thought through.

He said: "The overall scheme is good and there are lots of improvements but, as we do with everything in Northampton, we spoiled it by not paying attention to the details. We put a fishing platform on the only place that adversely affects a leisure activity."

Footmeadow is one of three parks given a recent facelift by Northampton Borough Council, with work also carried out on Millers Meadow and Victoria Park.

The 18-month regeneration project also included the creation of new pathways and landscaping, sensory gardens, a grass amphitheatre, wildlife habitats and children's play equipment.

Borough councillor Richard Church (Lib Dem, Kingsthorpe), who is cabinet member for regeneration, said the fishing platform at Footmeadow had been approved by the Environment Agency, the body responsible for waterway and river traffic.

He added: "Fishing is hugely popular and we received a lot of feedback from local anglers who asked for facilities that would benefit them.

"At each stage people were invited to have their say and comment on drawings and models showing different ideas for the park."