“Differences can also make a big difference in the workplace. Take Margaret Thatcher and Abraham Lincoln. When Thatcher formed a Cabinet, she wanted people who thought the same way she did – were ‘one of us’, as she put it. That meant she could be guaranteed a harmonious discussion. So much so, I was told, that she felt able to sum it up before it started and challenge anyone to disagree with her. Of course this led to tyranny, which always ends in disaster – in her case with her decision to introduce the unpopular Poll Tax that led to the end of her reign.”