At least one child in the school will have learned, probably through a familial connection, that there is a secret knot used by policemen. When tied with this knot, a tie cannot be peanutted - it simply releases, leaving the confounded crim holding a tie, and the rozzer free to throw them down the stairs.

When translated to the playground, however, this cunning trick will inevitably backfire as the peanutting bully will simply run off with your tie, leaving you to get in trouble for not wearing the correct uniform.