you need a leadloc fitting they come in about 4 different sizes, so you'll need the outside diameter of your lead pipe, or cut an inch off and take it to the plumbers merchants with you.
when fitting make sure the lead pipe is clean and round, not been squashed flat or you'll have trouble fitting the leadloc and it will not seal.
and take note of the size copper pipe your useing as well.
you can clean it up with a piece of henry cloth.
hi-spec plumbing
August 2007