Section 85K of Chapter 231 of the General Laws is hereby amended by striking out the first sentence of the first paragraph and inserting in place thereof the following sentence:

It shall not constitute a defense to any cause of action based on tort brought against a corporation, trustees of a trust, or members of an association that said corporation, trust or association is or at the time the cause of action arose was a charity; provided, that if (a) the tort was committed in the course of any activity carried on to accomplish directly the charitable purposes of such corporation, trust or association, and such corporation, trust or association derives more than fifty percent of its income from charitable gifts or donations or (b) such charitable corporation, trust or association has been established primarily for religious purposes, then liability in any such cause of action shall not exceed the sum of twenty thousand dollars, exclusive of interest and costs.