Though many firms believe large, open-plan workspaces help collaboration, in fact, unless staff are close "you might as well be in Belgium", said Millard.
"The trouble with open-plan offices is they are a one-size-fits-all model which actually fits nobody," she said at New Scientist Live in London on Monday.
"We're interrupted every three minutes. It takes us between eight and 20 minutes to get back into that thought process. E-mail. We get too much. Meetings, colleagues. It's all distracting.
"Is being switched on making us more productive? The answer is no. The problem of the future is switching off. The big damage is task-switching. You can tell you have been task- switching when you switch off your computer at night and find unsent e-mails still there because you were interrupted.
"So, we will become shoulderbag workers. Our technology has shrunk so we can literally get our office in a small bag."
However, Millard said offices were still important, if only for socialising.
"We need a balance between we and me," she added. - The Daily Telegraph