He didn't rush -- as many other Brits in Germany did -- to secure citizenship following the 2016 referendum vote to quit the EU.
Prime Minister Boris set out a plan for his country to become a global champion of free trade.
The EU's poorer members, also agreed to fight any move to cut the EU Cohesion Fund reserved for the bloc's weaker economies.
The British premier will note London has been told in earlier divorce talks with Brussels that it has the option of an ambitious trade deal.
Nigel Farage described Brexit as "the greatest moment in the modern history of our great nation".
Daily business between the United Kingdom and the EU will continue as before during an 11-month transition until the end of the year.
Official celebrations will be muted out of respect for half the population who wanted to stay in the EU and who remain fearful of what lies ahead.
The UK will leave the EU at midnight Brussels time (2300 GMT) on Friday, but remain under most EU rules during a transition until the end of the year.
The first leg of a five-nation tour that also takes in Ukraine comes with Britain facing a historic crossroads as it parts ways with the EU on Friday night.
On eve of Brexit, there is a strong possibility that the Bank of England will later Thursday announce its first interest rate cut in more than three years.
Brexit to officially take effect on Friday at 2300 GMT, midnight for most of continental Europe and 11:00 pm in Britain.
Johnson has been touting the prospects of a big new trade deal with the US that can fill the void of Britain's departure from the European Union on Friday.
After its divorce from the European Union takes effect on Friday night, Britain will be free to negotiate its own trade pacts.
British Prime Minister Boris Johnson insists that date will see Brexit "done".
Britain must now move onto so-called "equivalence", whereby financial firms agree to meet EU rules to maintain access to its market.
EU negotiator Michel Barnier said during the next phase of Brexit, Brussels and London will "have to rebuild everything".
Britain will become the first country to leave the EU at 2300 GMT on Friday, ending nearly five decades of membership.
The US has banned Huawei from the rollout of its next generation 5G mobile networks because of concerns.
Britons vote by 52 percent to 48 percent to become the first nation to leave the EU bloc.
As a permanent member of the UN Security Council, London wields veto power equal to Paris, Washington, Moscow and Beijing.
He will represent Queen Elizabeth II at the Church of Scotland's General Assembly from May 16 to 22.
The head of state's ceremonial approval of the withdrawal legislation allows Britain to leave its closest neighbours and trading partners.