Arthursson joined the firm in 2010 and progressed to become a director in the investment management arm in 2015.
He will join Quilter Cheviot as an investment manager in October this year.
The latest departure follows news that Arthurrson’s fellow director of investment management Peter Seamer, is also set to leave Arbuthnot later this year.
Arbuthnot Latham chairman Sir Henry Agnew boasted of the firm’s “momentous year” in its annual results released in March which revealed assets under management hit £920m and profits rose 51%.
