A Verulamium Park expert has waded in with his professional view on the core problems at the troubled lake.

Lake water quality has been at the centre of extensive debate since 2015, when avian botulism festering below the water surface killed about 100 birds and piles of smelly silt became an eyesore for summer tourists.

The Environment Agency (EA), Affinity Water, St Albans district council (SADC) and Hertfordshire county council’s (HCC) Countryside Management Service (CMS) are currently looking to solve the long-term water quality problems and will release a report next year.

But Roy May, 86, manager of the lake from 1968 to 1989, has said he is tired of rumours circulating that the lake has never been dredged or cleaned.

He emptied and unclogged it himself in the 1970s, dumping all of the silt on the Westminster Lodge field in a football pitch-sized pit about 20 inches deep.

A similar cleaning operation had also taken place in the 1950s before his time, he said.

Additionally, to make the chambers behind the sluice gates efficient, Roy used to demuck them weekly - and he is not sure when that job was last done.

He said if the lake is working effectively, water from the River Ver flows first into the small top lake, deposits silt there, and then gushes through a pipe to the bigger lake.

He explained it was designed this way because mud is easier to clean from the shallow little lake.

But Roy believes that the transfer pipe was blocked when soil for bird sanctuaries was poured into the water and since then the water stream from the River Ver had dwindled to mere inches.

He said: “The basic problem about the whole lake is there isn’t enough water going into the small lake to flow into the big lake.

“I realise that I probably know what to do about it but I can’t do anything about it myself. I have spoken to the council and the parks department and they have all my files on it.”

Roy is optimistic it can be fixed: “My personal feeling about it is that I am a bit disappointed with how it is but I don’t think the lake is anywhere near as bad as people make it out to be.”

Head of community services for SADC, Debbi White, said: “We are working with several partners including the Environment Agency, Affinity Water and Herts county council’s countryside management services on finding a long-term solution.”