Barry v Butlin 2 Moo PC 480:
The rules of law according to which cases of this nature are to be decided do not admit of any dispute so far as they are necessary to the determination of the present appeal, and they have been acquiesced in on both sides. These rules are two: The first, that the onus probandi lies in every case upon the party propounding a will and he must satisfy the conscience of the court that the instrument so propounded is the last will of a free and capable testator. The second is, that if a party writes or prepares a will under which he takes a benefit, that is a circumstance that ought generally to excite the suspicion of the court, and calls upon it to be vigilant and jealous in examining the evidence in support of the instrument, in favour of which it ought not to pronounce unless the suspicion is removed, and it is judicially satisfied that the paper propounded does express the true will of the deceased.
