—(1) Subject to this section, a person who for any period keeps a vehicle in respect of which tax under this Act has at any time become chargeable shall, whether or not it is still a mechanically propelled vehicle, be liable to pay tax under this Act in respect of the vehicle for that period.
(2) A person shall not be liable by virtue of subsection (1) to pay tax under this Act in respect of a vehicle —
for any period for which tax under this Act in respect of the vehicle has been paid and has not been repaid in consequence of the surrender of a licence;
for any calendar month in respect of which he has, in accordance with the rules, given notice to the Registrar that the vehicle will not be used or kept on a public road during that month or part thereof; and
for any period by reference to which there was calculated an amount ordered to be paid by him as a fine in pursuance of section 15(b).
(3) A person shall not, by virtue of subsection (2)(b), be exempt from his liability for any period under subsection (1) in respect of a vehicle if at any time during that period he or any other person with his consent uses or keeps the vehicle on a public road and no vehicle licence is in force for the vehicle at that time.
(4) For the purposes of subsection (3), the consent mentioned in that subsection shall be presumed to have been given unless the contrary is shown, but any use or keeping of the vehicle in question as respects which the vehicle is exempt by virtue of any written law for the time being in force from tax under this Act shall be disregarded.
(5) Sums payable under this section by way of tax in respect of a vehicle shall accrue due for every period of a calendar month at one-sixth of the semi-annual rate of tax applicable to the vehicle at the relevant time.