Street has been with Kensington for six years as director of sales, spending nearly 20 years in the mortgage industry as a whole.
He will assume responsibility for Sales, Marketing, New Business Operations, Underwriting, Customer Management and IT.
Other elements of the business, such as Treasury, Legal and Compliance, HR and Finance, are being integrated within Investec and will thus fall outside of Street's remit.
Charles Morley will continue as head of sales at Kensington, taking on primary responsibility for key account and other intermediary relationships.
Street said: “The market is going through some tough times at the moment, but we are lucky enough to have a great team of people and the full support of Investec.
"We have also taken steps to develop products, introduce a case booking system and launch a distribution panel to adapt to the current environment.
"You can be sure that when conditions do improve, Kensington will be right there at the forefront of the specialist mortgage market.”
