Prime minister David Cameron has defended his decision to fly to the Gulf and promote British defence exports to countries criticised over their human rights records.
Mr Cameron said he made "no apology" for helping Britain's defence industry do deals abroad.
His comments are expected to be made in a high-profile Mansion House speech in the City of London, where the PM is due to unveil plans to boost UK exports to growing economic markets around the globe.
The annual speech is traditionally the prime minister's highest-profile foreign affairs address of the year. But rather than talk about the crises in Syria or Iran or the row over the EU budget, Mr Cameron is expected to spell out his argument that the government should use its clout abroad to help British companies win the "global race" for jobs and business.
Mr Cameron came under fire last week for his three-day tour of the Gulf, in which he hoped to help sell 100 Typhoon jets - worth a total of £6 billion to the UK - to the UAE, Saudi Arabia and Oman.
On Monday evening, he will accept that some people are "squeamish" about the human rights records of some of the region's governments but he will insist that Britain has the toughest arms export rules in the world to prevent weapons being misused.
Mr Cameron will say: "We must support all sectors of the economy where we have a comparative advantage - and that includes defence.
"I understand why some people are a bit squeamish about me flying off round the world to help our defence industry do deals abroad.
"But there is a more fundamental point here. Every country in the world has a right to self-defence. And you cannot expect every country to be self-sufficient in providing the tanks, ships and planes needed.
"So when Britain has a very strong defence industry, with 300,000 jobs depending on it, it's right that we should be at the forefront of this market, supporting British jobs and British allies, and that's why last week, in the Gulf, I was pushing for new contracts for Typhoon jets worth billions of pounds and thousands of jobs.
"That's vital new business for Britain. And I make no apology for going out there and trying to help win it."
Mr Cameron is also expected to say he makes "no apology" for leading trade missions to Africa, Indonesia, China, India, Russia, Mexico, Brazil, Japan and Malaysia since coming to office two years ago.
"I know there are some people who say that's not real foreign policy. Or worse still, it's just globetrotting," Mr Cameron is expected to say.
"But I say - there is a global race out there to win jobs for Britain and I believe in leading from the front. So I make no apology for linking Britain to the fastest growing parts of the world."
He will announce the appointment of eight trade envoys to promote British businesses in growing economies, as well as an £8m pilot project headed by Trade Minister Lord Green to strengthen the capacity of overseas business groups in 20 key markets.
Mr Cameron will defend the City of London against critics who want to "trash" the banks, pointing out that the financial services sector contributes one-eighth of the government's revenue in taxes and underpins jobs for two million people.
"Yes, some utterly terrible mistakes were made," Mr Cameron is expected to say. "And they need to be addressed properly so they can never happen again.
"But those who think the answer is just to trash the banks, would end up trashing Britain.
"I say - recognise the enormous strength and potential of our financial sector; regulate it properly and get behind it."
Mr Cameron will say that the government's "modern industrial strategy" must support industries - like financial services - where the UK has a competitive edge and encourage high-growth sectors of the future.
And he will say that the strategy should "unleash the power of insurgents", by giving government backing to the fast-growing start-ups which are best at creating new jobs.