Hey guys do you ring 999 or 101?

Cuttlefish:

Franglais:
I`ve looked up the Highway Code reference for you, and it is written MUST NOT. It is a law.

Only in London

Highway code rule 244:
You MUST NOT park partially or wholly on the pavement in London

Highway code rule 244:
and should not do so elsewhere unless signs permit it.

Fair comment.
Rules in the Code which are legal requirements, and which you will be committing a criminal offense if you disobey, use the words “must/must not.” Violating other parts of the Code, which use the words “should/should not” or “do/do not”, can be used as evidence against you in Court, even if violating them is not an automatic criminal offense.