insurance required for test drive?

i told my dealer i wanted to take a cooper d for 'a good couple of hours' for a test drive & they reckon i need a cover note from my insurance. has anyone else faced this & do insurance companies charge?

feeds.mini2.com/~r/mini2forums/~3/129794388/showthread.php

Test Manager £55, 000 Insurance in City

Test Manager is highly sought after by an expanding and succesful Insurance company in London.

www.cityjobs.com/cgi-bin/vacdetails.pl?selection=921643488&src=rss_jbe