DAVID Cameron yesterday insisted he would "use every last drop of my energy" to sell Britain around the world as he defended his recent controversial arms sales trip to the Middle East amid the unfolding crisis in north Africa.

And in his keynote speech to the Conservative spring forum in Cardiff he defended the Coalition's cuts programme as moral while branding Ed Miliband and the Labour Party as cowards for not having the courage to sort out Britain's record deficit.

The Prime Minister told delegates how some people had been disdainful about his mission of "selling Britain to the world". He said critics "see me loading up a plane with businesspeople and say – that's not statesmanship, that's salesmanship. I say –attack all you want but do you think the Germans and the French and the Americans are all sitting at home waiting for business to fall into their lap? No. They's out selling their goods and so should we in this country as well".

He went on: "So let me tell you – while there are contracts to be won, jobs to be created, markets to be defended, I will be there ... not just because it's my job, not just because it's my duty, more than that, because I passionately believe, no, I know that this country can out-compete, out-perform, out-hustle the best in the world and I'm going to use every last drop of my energy to make sure that happens."

Last month, the PM was accompanied on a trip to Middle Eastern countries by representatives from defence firms such as BAE Systems, Thales UK and Qinetiq.

Among critics of his trade mission was the charity War On Want, which said: "As people in the Middle East risk their lives opposing authoritarian regimes, it is deplorable that David Cameron is seeking to exploit the crisis by promoting sales of weapons and torture equipment to the region."

On the economy, the party leader derided Gordon Brown's Government for leaving a "dreadful mess" with the nation spending £120 million a day on simply paying off debt.

He told conference that ministers were still uncovering tales of profligacy, explaining: "Because of those PFI contracts they signed, in one hospital it cost £333 to change a lightbulb. What on earth do they think they were doing? I say let's make this a lightbulb moment for the country – never, ever trust Labour with your money ever again."

However, Mr Cameron said that this was not just about economics but also about the "morality of it all".

He explained Labour were "happy just to pass on these debts to our children because they didn't have the guts to sort it out themselves".

The Tory leader insisted the Coalition had a credible plan to balance the books, admitting that the road ahead, particularly this year, would be hard.

"What we are doing might not be popular but it is the only way. The other way is the cowardly way, the irresponsible way and that's never, ever been the Conservative way."

As trailed, Mr Cameron also declared war on the "enemies of enterprise", who included Government bureaucrats concocting ridiculous rules, town hall officials taking forever on planning decisions and public sector procurement managers shutting out millions of small business people by always awarding contracts to big firms.

He also flagged up the March 23 Budget as the means by which the Government would "tear down the barriers to enterprise" and produce the "most pro-growth Budget this country has seen for a generation".