98 Sri Lanka Law Reports 1200012 S ri LR. submission was made by Mr. Rajapakse, learned Senior Counsel for the petitioner that the decision in the case of Dahanayake vs. De Silva(supra) is part of the law now in force. Even though learned Counsel for the petitioner did not support this argument with any authority, his contention was that irrespective of whether resort is made to the Ceylon (Parliamentary Elections) Order in Council, 1946, or not. Section 13(3)(c) of the Soulbury Constitution has been kept alive and in force now, in view of the decision of the Supreme Court in the case of Dahanayake vs. De Silva(supra). Therefore it was submitted by him that Section 13(3)(c) of the Soulbury Constitution should be considered for the purpose of giving effect to Article 91 (1)(e) of the 1978 Constitution. However this argument has to be considered in relation to Article 168( 1) of the 1978 Constitution. In other words the question in issue is whether, Article 168(1) would permit the Supreme Court decision in the case of Dahanayake vs. De Silvaisupraj to be treated as unwritten laws in force. On this matter the Supreme Court decision in the case of Walker Sons & Co. (U.K.) Ltd. vs. Gunatilake141is relevant and important. According to this five bench decision of the Supreme Court, the ratio decidendi of judicial decisions belongs to the category of unwritten laws within the meaning of Article 168(1). Therefore it is to be observed that the decision in the case of Dahanayake vs. De Silva(supra) where it has been held that under the 1972 Constitution, Section 13(3)(c) of the Soulbury Constitution was in operation to be considered for any disqualification by reason of contract, should now be considered as part of the unwritten laws in force for the purpose of Article 168( 1) of the 1978 Constitution. Once the highest Court of the land has interpreted the law it becomes part and parcel of the law in force. Decision in Dahanayake vs. De Silva being a decision of the Supreme Court, this Court is bound by this decision. The position regarding contracts under the Soulbury Constitution is laid down in Section 13(3)(c) of the said Constitution. Section 13(3)(c) provides as follows: