A South London council has been blasted for taking around 10 months to get rid of a fly-tipped mattress in a park.

A watchdog investigation found Kingston Council had refused to take responsibility for removing the mattress, which was dumped in a river running through a park it owns.

Amerdeep Somal, Local Government and Social Care Ombudsman, hit out at the council for taking so long to 'put right what should have been a simple task' to remove the mattress. She alleged the council appeared to put little pride into maintaining the park.

A council spokesperson said it is committed to preventing, clearing and prosecuting fly-tipping and protecting parks in Kingston. They added it aims to clear fly-tipped waste within 24 hours of it being reported.

A concerned resident, named Mr K in the ombudsman report, originally reported the fly-tipped mattress to the council in July last year and asked for it to be removed. Instead of sending a crew to get rid of the mattress, the council argued it was not its responsibility and told him to contact the Environment Agency instead.

Despite further correspondence, the council maintained its position and told Mr K to contact the ombudsman if he wanted to pursue his complaint. He approached the watchdog in October.

The ombudsman ruled it was the council's duty to remove the mattress as it was dumped in 'water on council land'. It said the authority failed to recognise its duty to deal with the waste as it had misapplied government guidance.

The report said: "The injustice to Mr K from this fault is clearly limited because the mattress is in a public place and does not have a direct effect on him. However, we accept the council's refusal to accept its duty has caused Mr K some frustration, especially given how protracted this matter has become, with it now being approximately 10 months since he first reported it.

"For this reason, we consider the council should write a formal letter of apology to Mr K, recognising its fault. We also consider the council should now act to remove the mattress, as is its duty, and that it should circulate guidance to all relevant officers, ensuring they understand the council's duties regarding fly-tipped waste." The council has since removed the mattress.

Ms Amerdeep said: "I am disappointed by the council's inflexibility in this case, and quite astonished it has taken such a long time to put right what should have been a simple task to remove the mattress from the river, which is barely ankle deep."

She added: "Fly-tipping of this type is a blight on local communities and affects people using the park for leisure and exercise. People care about their local environment and this could, and should, have been easily addressed."

A Kingston Council spokesperson said: "Our fly-tipping team aims to clear incidents within 24 hours once reported. We have also been one of the first councils to use technology and the 'internet of things' to protect our borough, with motion-activated cameras that notify us when a fly-tip may have occurred.

"More than this, the council's policies, priorities and actions show that we are dedicated to protecting and improving Kingston's public green spaces, parks, woodlands and riversides. These are vital for the physical and mental well-being of the borough's communities, and support habitats for the many species that also call Kingston home.

"Protecting our environment is everyone's responsibility – councils, residents, businesses and our regulators. We accept the ruling, which was primarily one of defining roles and responsibilities between councils and the Environment Agency.

"We will be publishing the formal response online in two media outlets next week."