but lost all of his clients' money in 1806 in a fraud perpetrated by Joseph Elkin Daniels. As a result, he probably had to sell or give up his broker's licence.

In 1812, Montefiore became a freemason, joining the Moira Lodge, No. 92 of the Premier Grand Lodge of England in London. From 1809 to 1814, Montefiore served in the Surrey Local Militia, rising to the rank of captain in the 3rd Surrey Local Militia's