British Olympic chiefs are to force athletes to sign a contract promising not to speak out about China's appalling human rights record – or face being banned from travelling to Beijing.

The move – which raises the spectre of the order given to the England football team to give a Nazi salute in Berlin in 1938 – immediately provoked a storm of protest.

The controversial clause has been inserted into athletes' contracts for the first time and forbids them from making any political comment about countries staging the Olympic Games.

It is contained in a 32-page document that will be presented to all those who reach the qualifying standard and are chosen for the team.

From the moment they sign up, the competitors – likely to include the Queen's granddaughter Zara Phillips and world record holder Paula Radcliffe...