In a speech at the Royal United Services Institute on Friday Mr Portillo will accuse western leaders of complacency and criticise Europe and the US for failing to back up strong rhetoric with firm military action.

The leader of the western world is accused of lacking resolve by Mr Portillo

The speech by the former Conservative Defence Secretary, who lost his seat at the last General Election, is being seen as another tentative step back onto the political stage.

Mr Portillo is popular on the right of the Tory party and was widely tipped to take over from Mr Hague until he lost his Enfield Southgate seat.

'West is lacking resolve'

A one-time protege of Lady Thatcher, Mr Portillo says the West is lacking resolve in dealing with the build-up of weapons of mass destruction in Iraq, nuclear tests by India and Pakistan.

Mr Portillo says the situation on the Indian sub-continent is deeply worrying

He says increased nuclear capability on the Indian sub-continent and the economic collapse of Russia, with its huge nuclear arsenal, have made for dangerous times.

Mr Portillo says: "We now face a greater chance of an actual nuclear exchange than at any time in the last 30 years.

"That is a serious degradation of our security and I can only conclude that we contributed to it by our neglect."

He criticises UK Prime Minister Tony Blair and US President Bill Clinton for failing to match their "impeccably firm rhetoric" with action.

'Empty sound bites'

Mr Portillo, who has made it clear he intends to bounce back and continue his political career, says the world's dictators "have not listened to our sound bites, but to our body language".

He says: "They have concluded that the world has become a safer place for them, and that must mean that it is now more dangerous for us."

Mr Portillo, who oversaw significant cuts while at the Ministry of Defence, says too many western countries were cutting their defence budgets.

He says: "When the dangers seem distant or merely unquantifiable, democratic politicians fail to take sufficient precautions or to spend enough on the security of their countries."

Mr Portillo says the west should give President Saddam a 'knockout blow'

Mr Portillo says the latest deal with Iraq's President Saddam Hussein - which averted the prospect of bombing raids on Baghdad - was "full of holes".

He says it is time we gave Saddam a "knockout blow".

Mr Portillo also warns the UK to "stop flirting" with the idea of replacing Nato with a European defence organisation.