I recently found this in the LTKA website. It's research that was done in 2002 by the Fraunhofer Research Institute in collaboration with the German Federal Institute for Information Technology Security.
It is a lengthy article but worth reading. It details a variety of easy ways to fool biometric scanners and the simple ways that the systems could be hacked - see www.heise.de/ct/english/02/11/114/
A quote near the end of the article reads:
"With the aid of data packets gathered by eavesdropping and some lines of Perl script we were able to reconstruct complete fingerprints"
Clarification on whether the systems fooled are the ones used in UK schools URGENTLY needs checking. Thankfully my children's fingerprints aren't on any systems - what a relief!