If after 14 days following the end of any income tax period the employer has paid no amount of earnings-related contributions to the Collector under paragraph 10 or 11 for that income tax period and there is reason to believe that the employer is liable to pay such contributions, the Collector, upon consideration of the employer’s record of past payments, may to the best of his judgement specify the amount of earnings-related contributions which he considers the employer is liable to pay and give notice to him of that amount.

The provisions of sub-paragraph (2) shall not apply if, during the period allowed in the notice, the employer pays to the Collector the full amount of earnings-related contributions which the employer is liable to pay under paragraph 10 or 11 for that income tax period, or the employer satisfies the Collector that no amount of such contributions is due.

The production of a certificate such as is mentioned in sub-paragraph (2) shall, until the contrary is established, be sufficient evidence that the employer is liable to pay to the Collector the amount shown in it; and any document purporting to be such a certificate as aforesaid shall be deemed to be such a certificate until the contrary is proved.

• Paragraph 16 shall apply, with any necessary modifications, to the amount shown in the certificate.

Where the employer has paid no amount of earnings-related contributions under paragraph 10 or 11 for any income tax periods, a notice may be given by the Collector under sub-paragraph (1) which extends to two or more consecutive income tax periods, and this Schedule shall have effect as if those income tax periods were the latest income tax period specified in the notice.

A notice may be given by the Collector under sub-paragraph (1) notwithstanding that an amount of earnings-related contributions has been paid to him by the employer under paragraph 10 or 11 for any income tax period, if, after seeking the employer’s explanation as to the amount of earnings-related contributions paid, the Collector is not satisfied that the amount so paid is the full amount which the employer is liable to pay to him for that period, and this paragraph shall have effect accordingly, save that sub-paragraph (2) shall not apply if, during the period allowed in the notice, the employer satisfies the Collector that no further amount of earnings-related contributions is due for the relevant income tax period.

Where, during the period allowed in a notice given by the Collector under sub-paragraph (1), the employer claims, but does not satisfy the Collector, that the payment of earnings-related contributions made in respect of any income tax period specified in the notice is the full amount of earnings-related contributions he is liable to pay to the Collector for that period, the employer may require the Collector to inspect the employer’s documents and records as if the Collector had called upon the employer to produce those documents and records in accordance with paragraph 26(1) and the provisions of paragraph 26 shall apply in relation to that inspection, and the notice given by the Collector under sub-paragraph (1) shall be disregarded in relation to any subsequent time.

Notwithstanding anything in this paragraph, if the employer pays any amount of earnings-related contributions certified by the Collector under it and that amount exceeds the amount which he would have been liable to pay in respect of that income tax period apart from this paragraph, he shall be entitled to set off such excess against any amount which he is liable to pay to the Collector under paragraph 10 or 11 for any subsequent income tax period.

If, after the end of the year, the employer renders the return required by paragraph 22(1) and the total earnings-related contributions he has paid in respect of that year in accordance with this Schedule exceeds the total amount of such contributions due for that year, any excess not otherwise recovered by set-off shall be repaid.