An angry man threw a boot at former Australian prime minister John Howard during a debate at Britain's Cambridge University, a quick-thinking student who caught the shoe said on Thursday.

Andrew Chapman, a senior officer at the Cambridge Union Society which organised the debate, told AFP how he stepped in to stop the boot thrown by an Australian man who had earlier branded Howard a "racist".

Howard "took it amazingly well -- he just brushed off the incident", according to the 20-year-old politics student and keen cricketer.

In the debate last Friday, Chapman had introduced Howard ahead of his speech on "leadership in the new century" but was heckled by a man shouting "go home, racist" to the former premier.

When Howard got up to speak, the man repeated this, shouting: "You make me ashamed to be Australian. Go home, racist."

A short while later, Chapman said, "he reached down to his foot, and I knew what was going to happen. I stood up, and got in between Howard and this gentlemen. He threw this boot and I caught it."

The man, whose identity remains unknown, was escorted out of the building by university security. He later returned to retrieve his boot, but "we politely turned down
this request," Chapman said.