Order and judgment (one paper), Supreme Court, New York County, entered on October 12, 1971, directing the parties to proceed to arbitration, unanimously reversed, on the law, and a new hearing directed, with $40 costs and disbursements of this appeal to appellant-to abide the event. The burden was on the claimant to show that the automobile involved in the accident was an uninsured vehicle. The only evidence to establish this was a letter from the purported insurer denying coverage. The admission of the letter into evidence was plainly error, and without it the right to arbitrate was not established. Concur — Kupferman, J. P., Murphy, Steuer and Tilzer, JJ.