David Davis is UK Secretary of State for Exiting the European Union. The opinions in this article belong to the author.

(CNN) It's more than two years since I last visited Washington DC.

Since then, there has been tremendous political and economic change on both sides of the Atlantic.

It is imperative that we now work together, as the closest of friends, to deliver a solution that works for both of our great continents.

From designing an immigration system that addresses the concerns of ordinary working people and fits the needs of business to ensuring we have regulation more tailored to the UK economy rather than the needs of 28 different economies, leaving the EU provides us with a large opportunity.

For the first time in over 40 years, we'll have the freedom to strike our own trade deals and deepen key relationships with old allies, including our closest ally, the US.

Brexit is not about Britain stepping back from the world, but jumping into the new opportunities it presents.

Outside of the EU, Britain will be nimbler, more open to innovation and technological change, at the same time as driving up global standards.

Using our might as the world's fifth largest economy -- we can become a true champion of free trade.

That should be in the interests of our close neighbours in Europe, as well as more far-reaching parts of the world.

From the very start of this process we've been clear that pursuing a new path will not come at the expense of our relationship with Europe. Our growth and prosperity will come alongside that of Europe, not instead of it.

Yesterday I completed the third round of negotiations to deliver a new partnership with the EU. It was constructive, but as I made clear, if we are to get the right deal we will need more flexibility.

JUST WATCHED UK suggests temporary customs union with EU Replay More Videos ... MUST WATCH UK suggests temporary customs union with EU 02:07

That deal is in both of our interests because after we've left, the UK will continue to buy Europe's goods and services, sell them ours, and our citizens will continue to travel, live and work across the continent.

It will address the unique circumstances around the border between Northern Ireland and Ireland -- making sure there is no hard border, and the Belfast ("Good Friday") Agreement is upheld in every way.

And it will also underline our continued cooperation with the EU on foreign affairs, and combating crime and terrorism.

We also want a new free trade agreement with the EU that allows for the freest possible trade in European goods and services between Britain and the EU's member states.

It should give companies operating in the UK the maximum freedom to trade with and operate within European markets -- and let European businesses do the same in Britain.

This is a deal of global economic importance which is in the shared interests of the UK and the EU. In 2016, while the UK exported £241 billion worth of goods and services to the EU, the UK imported £312 billion worth of goods and services from the EU.

The progress made this week at the formal negotiations means I'm hopeful we can start talking soon about a trade deal with the EU in the near future.

A successful economic relationship in Europe is in the interests of the US as well.

Britain and America have the closest defense relationship in the world, but it's often overlooked that we are each other's single largest foreign investors, supporting 2.2 million jobs.

An example of this is UK company JCB Ltd -- which manufactures machinery in both Savannah, Georgia, and Derbyshire in England, and recently confirmed one of the biggest single orders in its 71-year-old history to the US Army.

American corporations have invested nearly $600 billion in the UK, and there are many US subsidiaries in other EU member states doing business in Britain.

As the world's largest economic power and the world's fifth, together we can drive domestic and global growth.

In my speech today to business leaders at the US Chamber of Commerce, I'll outline how Brexit creates a huge opportunity for increasing liberalisation in services, improving standards around the world for workers and consumers, and through better harnessing technological developments.

I make no apologies for being ambitious for Britain, and the role it can play in the world once we leave the EU.

Because after we leave we can be a truly global Britain, competing on the world stage and a real champion for free trade.

And if we embark on that path together, with our American friends, there could be a very exciting future for us all.