Neither side would use nuclear weapons first” said Mr. Sha

Mr Sha former ambassador to the United Nations said the “no-first-use” policy should be scrapped as the US “builds new military alliances and as it increases its military presence in our neighbourhood”.

While only using nuclear weapons in retaliation gives China “the moral high ground”, Mr Sha argued it is “not suitable . . . unless China-US negotiations agree that neither side would use [nuclear weapons] first”.

He added: “For some time in the future, the US will see China as its main competitor and even its enemy.”

Since 1968, Beijing has adopted a policy where it would only use nuclear weapons in retaliation.

Western reports suggest China, the fifth country to develop nuclear weaponry, has an arsenal of between 250 to 350 missiles.

Hu Xijin, editor of the state-run outlet the Global Times, has said the People’s Liberation Army should enlarge its arsenal to 1,000 warheads.

He said: “We need to have a larger nuclear weapons arsenal to curb the US strategic ambitions and its impulses against China.

“You don’t beg for peaceful co-existence between countries but you need strategic tools to shape it.”