Clarification of *these* lines

[crr003]

Is there any variation allowed on the 1200mm in practice, or is the 1200 an absolute maximum?

To be in accordance with the regulations they must conform with the diagram. If they are wider than the measurement given (allowing for tolerances) they do not conform and are therefore technically not enforceable.

I've had a google and found this from Traffic Signs Manual Chapter 5:
23.19 As it is not possible to lay road markings to
precise dimensions, and to allow for markings
“spreading” in service, some tolerance in the
prescribed dimensions is permitted by regulation 12.
Specified values may vary by up to 5º for angular
measurements and by the tolerances quoted in
table 23-2 for linear dimensions. No tolerance is
permitted for those angular or linear dimensions
which are expressed as a maximum or minimum
value. A tolerance of plus or minus 25 mm is normally
allowed in the lateral positioning of lane lines.

Reading that (the bold bit), does it really mean that if the lines were 1201mm across they wouldn't conform? Sounds a bit harsh for laying a liquid down.

[MGF]

The court applies the 'de minimus' rule to the interpretation of the regs. That is, where the variation is so small as to be trivial the court will ignore it and treat it as compliant.

[dth]

These lines are there to reduce space probably as a result of RTCs and observed traffic behaviour.

The test as to whether it is safe will be when it goes wrong.

No part of these arrangements will be around an individual's knowledge, only around the fact that drivers are deemed to know the law and serious enough incidents will be judged, exceptionally by their peers, taking account of all the circumstances.

One way to think about it is 'more paint, more danger'