At midnight on New Year's Eve 1973, a British flag was raised in front of then-European Economic Community building in Brussels marking the start of the United Kingdom's full membership of the project. That day, British Prime Minister Edward Heath said membership would bring prosperity to his country.
On Monday, almost one year after UK voters decided to leave this 28-member and 500-million-citizen bloc, British negotiators walked into the European Union headquarters to begin talks with their Brussels counterparts on the terms of their divorce.
This is just the beginning of a technically, judicially and financially extraordinarily complex series of negotiations, which aim to end the interdependence formed by many treaties, laws and projects.
With Prime Minister Theresa May setting a Global Britain blueprint, the negotiation teams are scheduled to complete the talks in early 2019.
However, it is obvious that London is still unclear on how to pull itself out of this union in the aftermath of a string of terrorist attacks, the Grenfell Tower fire, and political instability in the wake of unnecessary damaging general election for the government.
By press time, the UK had not exchanged its position papers. The EU, represented by Michel Barnier, as chief negotiator for the 27 member states, has published two position papers, one on protecting the basic rights of EU citizens in the UK and the other on financial settlements, which it is estimated to range from 60 billion to 100 billion euros.
In its 11-page financial settlement position paper, the EU has clearly stated that the UK should clear its ties with all the EU institutions and the projects it has committed to as a full member in previous years, including the European Central Bank and European Investment Bank.
The EU also insists that the talks on ending the UK's EU membership must be finished before embarking on any negotiations for a new relationship.
Amid rising political difficulties, some in UK have started to question whether Brexit should go ahead, although May and her negotiators insist that it will.
Some even envision the EU's strategy of being super-tough in the negotiations may lead to a "no deal" scenario within the two-year negotiation time allowed by EU treaties. Then, the UK would fail to leave and the damage of European integration brought by UK's referendum could be avoided.
Of course, it is proper to envisage possible outcomes at the beginning of talks. But either way, Brexit has already been a hugely damaging consequence of democratic politics in the UK. This was a decision made by a national referendum, although many believe holding the referendum was a mistake.
Now the only rational thing to do is to maximize compromises and separate in a friendly way. But quicker re-engagement is of global significance and will bring stability to the changing geopolitical surroundings.
The EU has pledged to keep the negotiations extremely transparent, which is "politically correct" but surely would create long chain of debates among the media, the market, interests groups, politicians and the public.
And as shown in the EU's debt crisis years, too much debate can be misleading at some junctures and even the markets respond irrationally.
In a world filled with so many challenges and uncertainties, such risks should be avoided.
Monday's talks are just the very beginning of the haggling between London and Brussels. If they get beyond comparing notes, and agree on a common rational talk strategy, that will be encouraging.
The author Fu Jing is deputy chief of China Daily European Bureau.