There are few more perplexing phenomena than the workings of the modern liberal mind. Take one growing sub-species, the animal rights obsessive. It is almost impossible to understand the thought processes of those who consider the rights of animals to be more important than those of human beings. The latest outburst from Sir Paul McCartney is typical.

On today’s BBC Six O’Clock News, the former Beatle and his wife, Lady Heather, are shown watching gruesome footage from China of cats and dogs being killed and then stripped for their fur. The practice is indeed sickening and no decent person could be other than horrified.

Where Sir Paul’s moral indignation becomes simply warped, however, is in his next sentence. “I wouldn’t even dream of going over there to play, in the same way I wouldn’t go to a country that supported apartheid . . . It’s against every rule of humanity.” Sir Paul and his wife then call for a worldwide boycott of all Chinese goods. “If we can hit them in their pockets, maybe they’ll do something to stop this.”

China imprisons and executes thousands of dissidents who dare to criticise the regime. Sixteen years after the protest in Tiananmen Square dozens of those arrested remain in prison. One man, Yu Dongyue, is still imprisoned for having thrown paint on the portrait of Mao Zedong in Tiananmen Square, an act of “counterrevolutionary propaganda and incitement” for which he was sentenced to 20 years.

Sir Paul and Lady Heather are so exercised by the plight of some cats and dogs that they will now refuse to travel to China, and are demanding a worldwide boycott of Chinese goods.

As for the imprisonment and judicial murder of thousands of dissident human beings, not a pip from either of them.

Not that anyone should be surprised. It is the same liberal mindset that lavishes praise on Fidel Castro as a hero, rather than condemning him as a tyrant. Castro learnt well from his Soviet backers, and rounds up and imprisons opponents just as they did. In March 2003, 75 prisoners of conscience (as Amnesty has designated them) were sentenced to prison terms of up to 28 years for peacefully opposing the regime.

Sir Paul has worldwide fame. He could do untold good campaigning for his fellow human beings. Instead, he chooses to try to save a few animals. Go figure.