A thick black smelly substance has been spoiling the beauty of Verulamium Lake.

The lake, in the centre of St Albans Verulamium Park, has been a much loved attraction for tourists and residents for years.

However, a build-up of silt has become a concern for passers-by and St Albans District Council.

Research by officers from the council have found that bird droppings, leaves and fertiliser from nearby football pitches are all to blame for the black silt that clings to the sides of the lake.

Doug Price, of St Albans, now refuses to walk around the lake with his grandchild as the smell of from the silt is ‘disgusting’ and his wife, Liz, described the smell as ‘a strong chemical smell’.

Mel Field, 24, Coningsby Bank, said: “The whole lake needs emptying once the birds migrate, it’s disgusting. It’s a main focal point of St Albans and I’m ashamed to go down there.”

Last summer, an outbreak of avian botulism occurred, killing ducks and wildfowl. There is a concern that the virus could return this year if the water quality is not improved.

Nicola Coad, 38, of Broadstone Road, said: “It’s in appalling condition at both ends and smells like a sewer. It cannot be healthy for the birds and I did think that there are considerably less birds this year.”

Richard Shwe, head of community services for St Albans and District Council, said: “We are continuing to research short and long term solutions to deal with the build-up of silt at the edge of the lakes.

“Attempts to remove the silt by a JCB digger had some impact, but not as much as we would have liked. We are working with the Environment Agency on a scheme to restore the River Ver to its more natural, healthier state.”

Waste contractor, Veolia, plan to remove 60 tonnes of silt using a tanker fitted with a suction system. They hope to start work by the end of July.