An average of 410 bags of rubbish are removed from Epping Forest every day.
The figure - equivalent to 150,000 bags a year - is the result of professional fly-tipping and smaller scale littering and is not going to go down in coming years, says City of London Corporation head forest keeper Martin Newnham.
Syringes, tissues, used condoms, drug wrappers and other “pretty unpleasant products” are constantly found in the forest, as well as the large building waste, car batteries, animal bodies and hazardous materials discovered in the average two fly tips every day.
The ongoing problem poses a risk to forest visitors, can lead to animal injuries and deaths and costs thousands of pounds every year.
Rubbish attracts rats which target ground-roosting birds, and deer have been found with discarded plastic bags in their stomachs.
Mr Newnham said: “It is upsetting and frustrating, that is fair to say.
“I think everybody would share my frustration.
“It is an environmental crime – depending on the scale – and I think at a low level it is a lack of education and understanding.
“The more deliberate, wanton acts, that is frustrating.”
Fly-tipping rose by 40 per cent last year, with some 420 tonnes of waste removed by corporation staff and volunteers.
Mr Newnham said a more “robust” approach to the issue has recently been introduced, with the corporation using environmental legislation to prosecute offenders.
Rewards are given for information leading to prosecutions, he added.
However, he said the problem of littering from visitors, picnickers, drug users, people having sex and rough sleepers is not going to go away.
“I have got a finite amount of staff, a finite budget to work within.
“My aspiration is to try and improve the situation by having a more robust approach to the large scale dumping, but that is only one part of it.
“On a small scale, it is going to take a long time to change.
“If you have got rubbish, take it home with you.
“Maybe in 10 years’ time, if that common message goes out and is consistent, then we are winning… I do not ever think we will get to a point where we are reversing the trend, but if we can manage with the current level of resources we will be doing well - it is always going to be a problem.”
Asked if the corporation could do more to deal with the issue, Mr Newnham said he was opposed to adding more signs and bins because it could make the forest less “strange and mysterious”.
“We should try and preserve the natural aspect,” he said.
“The more signs we put up and the more bins we add, we turn it into a municipal park… what we want to do is encourage people to use it responsibly.”
“At the end of the day, it is everyone’s responsibility to pick up rubbish and take it home.”