Under 18's law
Criminal Justice Act 1988
(1)Any person who sells to a person under the age of eighteen years an article to which this section applies shall be guilty of an offence and liable on summary conviction to imprisonment for a term not exceeding six months, or a fine not exceeding level 5 on the standard scale, or both.
(2)Subject to subsection (3) below, this section applies to—
(a)any knife, knife blade or razor blade,
(b)any axe, and
(c)any other article which has a blade or which is sharply pointed and which is made or adapted for use for causing injury to the person.
(3)This section does not apply to any article described in—
(a)section 1 of the Restriction of Offensive Weapons Act 1959,
(b)an order made under section 141(2) of this Act, or
(c)an order made by the Secretary of State under this section.
(4)It shall be a defence for a person charged with an offence under subsection (1) above to prove that he took all reasonable precautions and exercised all due diligence to avoid the commission of the offence.
(5)The power to make an order under this section shall be exercisable by statutory instrument which shall be subject to annulment in pursuance of a resolution of either House of Parliament.
Criminal Justice Act 1988 (Offensive Weapons) (Exemption) Order 1996
(sale of knives or certain articles with blade or point to persons under eighteen) shall not apply to —
(a)a folding pocket-knife if the cutting edge of its blade does not exceed 7.62 centimetres (3 inches).