The National Trust is working to stop a pay-and-display car park in the Borrowdale Valley being taken over by massive camper vans at the weekends.
Kettlewell car park, on the edge of Derwentwater, usually provides parking for around 23,000 vehicles each year.
But increasing numbers of large camper vans have been occupying it for several days overnight – against the rules.
The problem started after lockdown but shows no signs of stopping, officials said.
It has led to a rise in litter and human waste being discarded at the popular beauty spot.
The problem of the car park was picked out at an open meeting in Borrowdale last week to discuss traffic and transport issues across the valley.
It is also limiting use of the facility to camper van owners who pitch up for the weekend – at the expense of other short-stay car parkers.
The trust has now applied to the Lake District National Park Authority seeking permission to install an adjustable height barrier to restrict usage to vehicles below a certain height.
A trust spokesman said: “During the two years of the pandemic the issue escalated significantly seeing a dramatic increase in the number of vehicles in the car park being occupied overnight. It has become increasingly common for camper vans to arrive during the Friday evening and remain until Sunday afternoon.
“These users will make no secret of their intention to remain and will set up additional camping infrastructure such as dining tables and washing lines. The number of complaints about the current usage of Kettlewell as a camping site has escalated significantly over the last two years and continue to be regularly received.”
The National Trust had thought the situation would improve as time passed, but said: “With visitor numbers returning to 2019 levels and usage returning to more traditional patterns on other sites, the situation at Kettlewell remains at its worst.
“We are aware that taking action to reduce the level of camping within Kettlewell will have an unfortunate side effect of limiting the use of legitimate users.”
However, there is limited access at a number of NT car parks including Fell Foot, Windermere and Rectory Field, Windermere, where a barrier is used to close the entrance and exit at 8pm and the site remaining closed until 9.30am. An external security company charges a £50 call-out fee if a member of the public wants their vehicles released after closure.