—In a proceeding pursuant to CPLR article 75 to stay arbitration of an uninsured motorist claim, John Hopkins, Jr., appeals from a judgment of the Supreme Court, Nassau County (O’Shaugnessy, J.), dated June 9, 1993, which granted the petition.
Ordered that the judgment is reversed, on the law, with costs, the petition is dismissed, and the parties are directed to proceed to arbitration.
It is well-settled that an insurance carrier may not disclaim liability if it fails to give the insured timely notice of the disclaimer "as soon as is reasonably possible after it first learns of the accident or grounds for disclaimer of liability or denial of coverage” (Hartford Ins. Co. v County of Nassau, 46 NY2d 1028, 1029; New York Cent. Mut. Fire Ins. Co. v Markowitz, 147 AD2d 461, 462). Moreover, the foregoing rule is applicable even if the insured or the injured claimant has in the first instance failed to provide the carrier with timely notice of an accident (see, Kramer v Interboro Mut. Indem. Ins. Co., 176 AD2d 308; New York Cent. Mut. Fire Ins. Co. v Markowitz, supra). Where there is no explanation given by a carrier, a delay of two months in providing such notice is unreasonable as a matter of law (Hartford Ins. Co. v County of Nassau, supra).
Although the parties agree that notice of the claim was first given in a letter dated June 4, 1992, the petitioner argues that the starting date for the purpose of determining whether any delay on its part in disclaiming was unreasonable should be *519October 5, 1992, when it received, inter alia, the police report of the accident. However, even accepting the validity of this argument, there would still exist an unreasonable delay of approximately four months’ length. We stress in this regard that the petitioner has failed to substantiate with documentary evidence its conclusory assertion that it denied the appellant’s claim on November 11, 1992. Insofar as the record indicates, the appellant was not notified of the disclaimer until he received the "notice of petition for stay of arbitration” which was served on or about February 8, 1993. Sullivan, J. P., Altman and Friedmann, JJ., concur.