Why not just cut to the chase and declare that all of Britain must be constructed and furnished by Playskool and Little Tikes, with generous amounts of foam padding on everything.
Here ya go, Britain! Nothing here with which to harm anyone!
And they could climb up on the roof, jump off, and hurt themselves, so we'll need to dispense with that.
I think that the nanny state will not be happy until everyone is living in a foam-padded room.
The people in your simulation still have hands (fists), arms (elbows), knees, feet, teeth, and foreheads. In addition, there are also sticks, rocks, and various other things laying about. Also, with sufficient motivation, they could rip that door off and beat one another to death with it. To ensure maximum safety, I recommend removing all the things I mentioned, and trying again.
Oh no! That playhouse doesn't look safe! A child could stick a smaller child's neck in the doorway and use the leverage provided by the hinge to break the smaller child's neck!
take it one step further - Only baby food will be allowed. No more need for those nasty knifes and forks. Yes, forks, they have those pointy things on them. And the only permissible writing instrument would be the jumbo crayon.
Next, a nation on Thorazine (except for the elites, of course).