18. —(1) Where the Minister gives a direction under this Part or the Act of 1998, the direction shall be in writing and be addressed to the person or undertaking concerned and as soon as practicable, be sent or given in any of the following ways:

(a) by delivering it to the person or undertaking;

(b) by leaving it at the address at which the person or undertaking carries on business;

(c) by sending it by pre-paid registered post to the address at which the person or undertaking carries on business;

(d) if an address for the service of directions or notifications has been furnished by the person or undertaking to the Minister, by leaving it at, or sending it by pre-paid registered post to, that address, or

(e) in any case where the Minister considers that the immediate giving of the direction is required, by sending it, by means of a facsimile machine or by electronic mail, to a device or facility for the reception of facsimiles or electronic mail located at the address at which the person or undertaking ordinarily carries on business or, if an address for the service of notices has been furnished by the person or undertaking, that address, provided that the sender's transmission of the total number of pages of the direction or notification, as the case may be, or the sender's facility for the reception of electronic mail generates a message confirming receipt of the electronic mail.

(2) A person to whom the Minister issues or gives a direction under this Part or the Act of 1998 shall comply with the direction.

(3) In this section “undertaking” means Aer Rianta, Dublin Airport Authority, Cork Airport Authority or Shannon Airport Authority, or any of their subsidiaries as the case may be.