The NAO said in a report that border staff managed to cut immigration queue times down during the London Olympics, but only at the expense of neglecting their other duties.
Ok, so the Tech used is inefficient, as repeated above by most commentards, but no-one seems to have noticed that this report is based on a period when the number of incoming visitors to the UK had almost doubled compared to normal, and yet the staffing levels were not adequately increased to deal with this.
It's hardly surprising, then, that the Border staff did the best they could with what was available to them, and prioritised the queues of incoming travelers over their other duties, and yet now they are being admonished for doing that. Had they ignored the queues and continued to carry out all their duties equally, I'm sure they would have been criticised for that as well
I am not in any way connected with the immigration service or any other affiliated organisation, by the way, I just think it's typical UK government behaviour to blame anyone other than the policy makers (themselves) when a lack of forward planning is highlighted.