rover 25 2002?

Failed alternator drive belt?
Failed alternator?
Failed wiring in alternator circuits?

With the engine running yuu should see about 14.4V across the battery.

Useful resources all over the place.

Here's a couple:

http://forums.moneysavingexpert.com/showthread.php?t=4879175

http://www.honestjohn.co.uk/forum/post/index.htm?t=99239

XX
December 2015