U.K. children are deterred from using school toilets in secondary schools because they are dirty – and occupied by smokers and bullies, a survey warns.

BBC reports that a quarter of the 300 children surveyed by experts from the London School of Hygiene and Tropical Medicine said they avoided toilets if at all possible.

Speaking before Friday’s Global Handwashing Day, the scientists said facilities were "dirty and inadequate."

More than a third (36%) said their toilets were never clean, with 42% saying soap was only available sometimes, and almost a fifth (19%) said there was never any soap.

Nearly 40% of secondary school girls reported ”holding it in” so they didn’t have to go to the toilet.

And 16% of secondary school boys reported "bad things" happening in the toilets, making them wary of going in there.

Around 150 primary school children were also questioned in the survey, but they reported far fewer problems with their toilets.

Dr Val Curtis, director of the London School of Hygiene and Tropical Medicine’s Hygiene Centre, who led the research, said,

"It would be easy to blame laziness on the part of the kids for this state of affairs, but clearly the problem lies with inadequate and dirty facilities, particularly in secondary schools."

Proper handwashing requires access to proper tools.