Power steering belt

[raw]

Hi all

Cars done a strange thing. For the second time now my power steering belt has made a bid for freedom. Last time it got caught up on the oil filter and I refitted it but this time it's gone and manages to flip the alternator belt on the way out.

Both occasions have been on motorway runs and it's been fine for a month in between. On neither occasion has the tensioner loosened off.

Any ideas?

Rich