It not being illegal is not a good thing. Apparently evidence tampering is cool in the UK?
I never said it was a good thing — of course evidence tampering is utterly unacceptable. The systems here simply hew closely to expected standards of behaviour from institutions, and in any event there are a range of mechanisms to address the behaviour without needing to criminalise it.
My understanding is that expate communication with the judge or a judges staff in a court case is not legal (unless allowed under very specific situations).