This was appeal of Federal Court Judge’s decision allowing respondents’ appeals from prothonotary’s decision. Prothonotary struck out notices of application filed by respondents in Federal Court. Notices of application challenged issuance of search warrants under s. 487 of Criminal Code (Can.). Notices of application were struck out as abuse of process. On appeal judge set aside prothonotary’s decision. Appeal allowed. Neither prothonatary nor judge directly addressed doctrine of collateral attack. Search warrants issued by provincial authorities were orders. Orders must be challenged in forum in which they were made. Whether CRA’s practice of obtaining search warrants exclusively under s. 487 of Code was legal should be decided by court having jurisdiction over warrants. Fact that respondents’ applications were not obviously doomed to failure on merits did not make them any less of collateral attack. Federal judge erred in law in failing to give effect to doctrine of collateral attack in deciding whether respondents’ notices of application should be allowed to proceed. Siggelkow v. Canada (Attorney General) (Apr. 24, 2012, F.C.A., Pelletier, Gauthier and Stratas JJ.A., File No. A-267-11) Decision at 205 A.C.W.S. (3d) 7 was reversed. 102 W.C.B. (2d) 415 (10 pp.).