On September 15, 1978, the plaintiff, Hartford Federal Savings and Loan Association, commenced four separate mortgage foreclosure proceedings against the defendant Stanley V. Tucker (hereinafter the defendant), as owner of the *608equity of redemption, and other defendants, concerning four properties located at 65 and 69 Amity Street, 963 Capitol Avenue and 38 South Whitney Street, all in Hartford. On December 1, 1978, pursuant to G-eneral Statutes § 52-87, concerning notices to out-of-state defendants, the defendant’s motion for a statutory continuance was granted.
Upon written motion of the plaintiff, the trial court appointed a rent receiver for all four properties. Subsequently, on March 13, 1979, the plaintiff moved for default for failure to plead and for judgment against the defendant Tucker. The motion for default came before the court on April 20, 1979. On April 20, 1979, before court opened, the defendant filed his answer, special defenses and counterclaims. The trial court, however, held that the defendant’s pleadings were “improper,” “improperly filed” and “not in accordance with the Practice Book,” and refused to accept them. The court then ordered that a default be entered against the defendant for failure to plead. The plaintiff thereafter pursued its motion for judgment which was heard and argued by the parties on April 20, 1979, and April 23, 1979.
The court ordered a foreclosure by sale for the premises at 65 Amity Street and 38 South Whitney Street, and strict foreclosure for the premises at 69 Amity Street and 963 Capitol Avenue. Prom the judgments rendered the defendant appealed to this court.
On appeal, the defendant has briefed due process attacks on §§ 504 through 510 of the 1978 Practice Book and on the strict foreclosure procedures. These are claims of first impression which this court *609cannot reach at this time since they were not ruled upon by the trial court. Pele v. Danbury, 166 Conn. 364, 366, 349 A.2d 825 (1974).
We note, however, that it is a reasonable inference from the record that the trial judge refused to accept the defendant’s pleadings on April 20 before the hearing on the motion for default because he believed they were untimely filed. Under General Statutes § 52-121,1 “[a]ny pleading in any civil action may be filed after the expiration of the time fixed by statute or by any rule of court until the court has heard any motion for judgment by default or nonsuit for failure to plead which has been filed in writing with the clerk of the court in which such cause is pending. ...” Thus, under the provisions of the statute, the defendant’s pleadings were not untimely at the time they were filed. An oversight of a clearly applicable statute can be considered plain error.2
*610There is error, the judgment is set aside and the case is remanded for further proceedings in accordance with this opinion.