Entail Improvement Act 1770 (c. 51)

21 but neglecting so to do, and not recovering one third part of rents, etc. before his decease, shall cease to be creditor to subsequent heirs for such sum; and such third part to be recoverable only from executors, etc. of first heirs, etc. and surplus from subsequent succeeding heirs. S

Provided always, that the executor, assignee, or other person or persons, having right to the claim arising from money expended by the proprietor of an entailed estate, who shall neglect to require the next, or any other succeeding heir or heirs to pay, and shall allow such succeeding heir or heirs to die without recovering payment from him or them to the amount of one third part at least, of the rents that shall have become due to such heir or heirs, shall cease to be creditor to the subsequent succeeding heir or heirs respectively, to the extent of one third part of the rents which shall have become due to the heir or heirs so deceasing as aforesaid; and shall be intitled to recover payment of his claim to the extent of such third part of the rents, from the executors or heirs only of the first or any other succeeding heir or heirs, in any other estate than the entailed estate; and shall be intitled to recover payment of the surplus of his claim, if any be, and no more, from the subsequent succeeding heir or heirs respectively.