There are two interesting and partially overlapping events in the UK at the end of March 2012.

One is a full workshop in Oxford, running 26-30 March, where a number of high-quality European speakers are invited, and is funded by US Office of Naval Research.
http://www.cs.ox.ac.uk/qisw2012/index.html

The other is just a one-day portion of BAMC 2012 at UCL London, which will feature a morning minisymposium on Quantum Dynamics, and an afternoon minisymposium on Quantum Information, all on 28 March.
http://www.ucl.ac.uk/math/BAMC-2012/index.htm