(a) If the request is not made in conformity with the provisions of this article; (b) If the requested State Party considers that execution of the request is likely to prejudice its sovereignty, security, ordre public or other essential interests; (c) If the authorities of the requested State Party would be prohibited by its domestic law from carrying out the action requested with regard to any similar offence, had it been subject to investigation, prosecution or judicial proceedings under their own jurisdiction; (d) If it would be contrary to the legal system of the requested State Party relating to mutual legal assistance for the request to be granted. 22. States Parties may not refuse a request for mutual legal assistance on the sole ground that the offence is also considered to involve fiscal matters. 23. Reasons shall be given for any refusal of mutual legal assistance. 24. The requested State Party shall execute the request for mutual legal assistance as soon as possible and shall take as full account as possible of any deadlines suggested by the requesting State Party and for which reasons are given, preferably in the request. The requested State Party shall respond to reasonable requests by the requesting State Party on progress of its handling of the request. The requesting State Party shall promptly inform the requested State Party when the assistance sought is no longer required. 25. Mutual legal assistance may be postponed by the requested State Party on the ground that it interferes with an ongoing investigation, prosecution or judicial proceeding. 26. Before refusing a request pursuant to paragraph 21 of this article or postponing its execution pursuant to paragraph 25 of this article, the requested State Party shall consult with the requesting State Party to consider whether assistance may be granted subject to such terms and conditions as it deems necessary. If the requesting State Party accepts assistance subject to those conditions, it shall comply with the conditions. 27. Without prejudice to the application of paragraph 12 of this article, a witness, expert or other person who, at the request of the requesting State Party, consents to give evidence in a proceeding or to assist in an investigation, prosecution or judicial proceeding in the territory of the requesting State Party shall not be prosecuted, detained, punished or subjected to any other restriction 24