placing number 12 in col d

Hi all,
Here is the problem
Column D is an empty column.Column E contains data.The number of rows are variable.Is there a way I can place the number 12 into empty column D,but stops when the data in corresponding column E ends.
Any help fully appreciated
Kind Regards
BIF

HI Kaper,
Brilliant
The code works perfectly,many many thanks for that,and for your quick response.
Kind Regards
BIF