http://ubuntuforums.org/showthread.php?p=5683172

As a backports newbie, I was a bit lost at first, but got this working finally by:

1. enabling hardy-backports in /etc/apt/sources.list

2. pinning backports to a lower priority of 400 by writing the following in /etc/apt/preferences

Code:

Package: *
Pin: release a=hardy-backports
Pin-Priority: 400

3. install subversion 1.5

Code:

sudo apt-get update
sudo apt-get -t hardy-backports install subversion

The -t is the key, it temporarily boosts the priority of backports repository so that apt looks there first for this particular installation.
