The days of "cops and robbers" may be in the past for many young children, as most nurseries are now banning them from bringing in and playing with toy weapons, according to a poll.
The survey also suggests that for a small number, superhero costumes are getting the thumbs down.
There is a fear that toy guns and swords can encourage aggression and violence, according to Sue Learner, editor of daynurseries.co.uk, which published the poll.
But she added that banning pretend weapons is "controlling children's imaginative play".
The survey found that around four in five (79%) of those questioned said that toy weapons are not allowed in their nursery, while about a fifth (21%) said they were permitted.
In addition, one in 20 (5%) of the nursery workers polled said their nursery has banned superhero costumes, with the majority (95%) saying they are allowed.
Ms Learner said: "It is interesting that this is such a contentious issue. There is this fear toy guns and swords encourage aggression and violence and create a noisy, chaotic atmosphere.
"I realise many nurseries are under pressure from parents due to these perceptions. Yet if we ban toy weapons, we are controlling children's imaginative play.
"Playing cops and robbers or baddies vs goodies are physical games involving running, crouching and hiding.
"We should be encouraging open-ended physical play, not limiting it and shutting it down.
"I have three sons who all played with toy guns and swords and they haven't turned into aggressive, gun-toting teenagers.
"In a society where obesity is on the increase we need to engage with children and offer them toys which stimulate energetic role play."
Greg Lane, manager of the Soho Family Centre, part of the London Early Years Foundation, said he had worked for other nurseries that had been very strict about banning toy weapons, but that he did not think this was realistic, suggesting as an example that a nursery may be based in a community where guns are an issue.
"Censoring it or pretending it does not exist is not appropriate, or realistic," he said.
"How we approach it at my nursery is that they are not banned, but we don't encourage it. So I wouldn't say, 'Oh, tomorrow what are you going to bring in? Please bring in your pretend gun.'
"But they are not banned."
Mr Lane added: "I think you have to broaden it out. It's very connected to role play and superhero play has quite a moral edge with children, it's very popular. For example, if they're coming in and they have a lightsabre, is that a bad thing?
"Because it is technically a weapon after all. But I wouldn't ban that because there is kind of a moral purpose behind it and if you manage it appropriately and talk to the children about what they're doing - if they're rescuing somebody, if they're protecting somebody - it's part of their play. It's very subtle but it's quite profound."
David Wright, co-owner of the Paintpots nursery group based in Southampton, said he takes a considered approach to the issue.
"My take on it is that as adults, we project our own prejudices, our own thoughts and our own fears on to children's play."
He went on to say: "If children are engaged in role play, which involves guns, weapons, superhero play or whatever, they are not going through the same processes related to what we see in the media, and what we perceive.
"I think we have to make that distinction between children's imagination and what goes on in the real world."
He added: "I'm not banning those kinds of activities, what we don't do is actively encourage children to bring guns in."
On superhero costumes, Ms Learner said: "Nurseries have told us they find, when children dress in superhero costumes, they try and take on the persona of the superhero and will run around trying to 'kill' people and shouting 'You are going to die, bang bang'.
"They say children can get hyped up and take a long time to calm down and it can be hard to engage them in other activities."
- The survey questioned 1,125 nursery owners, managers and staff in February and March.