Looks like someone dumped a lot of shares at around 14:50, probably intentionally triggering stop loss sells.
I wonder if these are the same people who put in stupid bids prior to trading and retract them at about 10:06, just before the opening. Sick & unfair & against the rules.
Looking forward to the time these people try to drive the sp upwards again. Strong buy at this level! No money left in the till :\