Britain can enjoy trade with the European Union that is "at least as free" as it is now despite Brexit, Liam Fox has claimed.

The international trade secretary said it was in the interests of EU countries not to erect tariffs and instead to offer the UK free and open trade after it left the Brussels bloc. Any other arrangement, he argued, could harm European nations because they exported more to the UK than vice versa.

The Scot spoke as the debate continued over whether the Conservative Government should pursue a "hard Brexit" outside the European single market free trade zone, so it could get full control of its borders.

The issue is set to dominate the upcoming Tory conference, which begins in Birmingham on Sunday, although Theresa May has taken an unusual step in scheduling a major speech for that day to address Brexit in a possible attempt to deal with it early at the four-day conference.

Answering questions after a keynote speech in Manchester, Dr Fox suggested Britain could maintain the benefits of the single market post-Brexit.

"Protectionism never actually helps anybody at all and, as we move into a post-Brexit arena, we want trade to be as free and as open as possible," he declared.

"And don't just look at it from the UK perspective, the European Union has a massive surplus in goods with the UK. Who does it harm more if we end up in a new tariff environment? Does it harm more those who sell more to the UK, or the UK?” he asked.

The secretary of state, one of three chief Brexiters whose role will be to fashion a British Brexit deal, insisted it was in everybody's interests that the UK had at least as free a trading environment as it had today.

"Everything else may not harm the politicians and institutions but it will harm the people of Europe, and it's the people of Europe who should be at the forefront of our thoughts during that period," he said.

Earlier, Tory grandee Ken Clarke, the pro-EU former chancellor, claimed the Prime Minister was running a "government with no policies," which had no idea how to carry out Britain's exit from the EU.

In his speech, Dr Fox said free trade and globalisation had transformed the world for the better, opening new markets and lifting the poor out of poverty, but a "bright future" was being darkened by the "shadow of protectionism".

He said the fruits of growth had not always been equally shared, it has fostered insecurity and it was easier to identify the losers of globalisation than the winners.

But it was the "duty" of politicians to explain the benefits and not "pander" to short-term protectionist instincts.

"Competition leads to innovation and it's innovation that powers progress. Far from being a race to the bottom, free trade is often a ladder to the top."

He said Britain will "lead the charge" to continue to argue for free trade "as a badge of honour."

The cabinet minister said only 11 per cent of UK businesses exported goods and services so British firms needed to export more to take advantage of global markets and get the UK's trade deficit down.

His comments came days after he sparked controversy by branding British bosses "lazy" because he claimed they would rather play golf than cut a deal.

He questioned whether the UK's lack of exports was the fault of the culture of British business or the Government's fault for not giving encouragement, or both.

But he added: "You know, when I was a doctor, my job was not to tell people what they wanted to hear, it was tell them what they needed to hear so that we could put things right. Now if it applies to medicine, why does the same ethics not apply to politics? A question I have always wondered."

Dr Fox spoke after Italian Prime Minister Matteo Renzi insisted Britain would not have full access to the single market while curbing immigration, saying it would be "impossible" for British people to have more rights than others outside the EU.

European leaders have repeatedly asserted that Britain cannot enjoy the benefits of the free trade zone without allowing the free movement of EU citizens - seen as unpalatable by Mrs May.

In his speech, which contained no policy announcements, Dr Fox said the referendum could herald Britain embracing a "post-geography trading world".

He said the "brave and historic" decision of the British people did not mean the country was cutting itself off from Europe but, rather, shaping a new trading role with the world.

He told a business audience at Manchester Town Hall: "The British people have presented us with a glorious opportunity to re-set our global trading relationships, place ourselves back at the centre of an increasingly inter-connected world and build an economy that works for all."

Nick Clegg, the former deputy prime minister, branded Dr Fox's speech "delusional" and urged him to make public the economic impact of leaving the single market.

The Liberal Democrat EU spokesman said: "Liam Fox is delusional about the impact of Brexit on British trade with the rest of the world. Unbelievably, he claims to be 'taking an axe to red tape across borders'.

"The truth is that leaving the EU's customs union and single market will bring a deluge of new Brexit red tape down on the heads of British businesses who export to the continent. Fox needs to come clean about the true impact this will have on our exporters," he added.

Earlier, Tory former Cabinet minister Nicky Morgan urged Mrs May to make public her Brexit strategy as the milestone of 100 days since the referendum approaches on Saturday.

Mrs Morgan told the BBC Radio 4 Today programme that the balance between access to the single market and freedom of movement was "at the heart" of the Brexit issue and she urged the PM to hurry up and make her position clear.

She cast doubt over statements coming out of Europe suggesting there would be no budge on the issue, saying "nobody starts the beginning of the negotiating process where they end up".

Meanwhile, a German business boss said Britain had to pursue a hard Brexit if it wanted control over immigration.

Markus Kerber, head of the BDI, which represents German industry, told Today: "So what do we think the British Government wants? I can tell you straight away, it's not what the continental Europeans are willing or even able to give."