Certainly (sort of) working in March
I got plenty of time to study this contraption whilst waiting in immigration in March (as usual there were two people on hand to check 700 or so people who'd just arrived in two 777s). Its a posh glass booth with sliding doors that open and close in an excitingly swoopy manner.
During my incarceration in the concrete immigration bunker at Gatwick I saw one whole person use the iris system. He went towards it, the doors opened (in a swoopy way that was quite exciting), he mucked around inside for a while, someone came over and prodded the machine for a few minutes, checked his passport and he left.
So apart from the need for constant human intervention and that it takes about ten times longer than being stared at by a human, this is clearly a major step forward for technology. And the swooping doors are really very exciting.
BTW. If biometrics are so fool-proof, just why did Liam Byrne need to be enrolled twice?