Here is the hypothetical:  Plaintiff hires attorney A to prosecute an action against the State of New York, and does not timely file a notice of claim.  There is still time within the statute of limitations to file a motion seeking leave to file a late notice of claim. 

Plaintiff hires attorney B to sue for legal malpractice. Is Attorney B required to try to mitigate by seeking leave?  If Attorney B does not, is he subject to third-party litigation?

The case of Eugene Cacho, v.The Law Offices of Louis Venezia and Louis Venezia,
102554/2006 SUPREME COURT OF NEW YORK, RICHMOND COUNTY ,2008 NY Slip Op 50111U;  says no.  Justice McMahon writes:

"With respect to the motion at hand, generally, where a law firm is retained for the limited and express purpose of representing a client in a legal malpractice action, they do not have a duty to prosecute the underlying claim, if one still lies (see Northrop v. Thorsen, AD3d , 2007 N.Y. App. Div. LEXIS 12903 [2d Dept., Dec. 18, 2007][finding that an attorney retained "in a separate matter, before a separate tribunal, and for a different purpose" does not require him to mitigate damages in the underlying claims); Johnson v. Berger, 193 AD2d 784, 786, 598 N.Y.S.2d 270 [2d Dept., 1993][holding that a law firm’s failure to preserve an estate’s assets, when retained for the limited purpose of prosecuting a legal malpractice action "did not contribute to or aggravate the plaintiffs’ damages arising from the former attorneys’ alleged legal malpractice"]).

Here, third-party defendant’s have established entitlement to judgment in accordance with CPLR § 3211(a)(1) and (a)(7). The retainer [**4] agreement is clear and specific, detailing that the representation by the third-party defendants is for "damages arising from personal injuries sustained by Eugene Cacho as a result of legal malpractice." Further, the cases cited by the defendant/third-party plaintiff’s are distinguishable from the instant matter in that here, the third-party defendant Minchew was not hired as successor counsel to prosecute the personal injury claim, but rather on a different matter, in front of a different Judge and for a different purpose (Northrop v. Thorsen, AD3d , 2007 N.Y. App. Div. LEXIS 12903 [2d Dept., Dec. 18, 2007]). As a result, defendant Minchew is under no obligation to file a late notice of claim and therefore, dismissal of the third-party complaint is warranted (see CPLR § 3211 [a][1], [a][7]; Northrop v. Thorsen, AD3d , 2007 N.Y. App. Div. LEXIS 12903 [2d Dept., Dec 18, 2007]; Johnson v. Berger, 193 AD2d at 786). "