The plaintiff’s motion to increase the ad damnum in the writ was properly allowed for the reasons stated by the trial judge in his memorandum and order thereon. Judgment is to be entered for the plaintiff on the verdict returned by the jury. The plaintiff is to have double costs from September 3, 1974, together with interest from that date on the amount of the verdict (and on the interest thereon), to be computed at the rate of twelve per cent per annum. G. L. c. 211A, § 15. J. L. Vaughan Heating & Engr. Co. Inc. v. Cantor, ante, 709 (1975).

So ordered.