Haowu Dong, Grade 4, Shenzhen College of International Education

Leaving the European Union (EU) may be Britain’s biggest change in trade and foreign policy since World War II.

With less than five months before the British schedule to leave the EU on March 29 next year, both sides are beefing up efforts to reach agreement on a draft withdrawal deal, making clear the terms of the separation, a transition period and a solution to a new land border.

There are three key issues in the first phase of negotiations — citizen rights of the two parties, the divorce fee and the administration of the 500-km border between Ireland and the British territory of Northern Ireland, the only land border between the U.K. and the EU. Although the first two issues have been basically solved, the third one — the border dispute — could also bottleneck and even sink the negotiations on Britain’s exit process and lead to no-deal Brexit.

No-deal Brexit will bring benefit to nobody and is even potentially dangerous if London really crashes out without an agreement.

From the political perspective, no-deal Brexit not only reflects the intense interest confrontation between the U.K. and the EU, but also signals the poor political mutual trust between them. Meanwhile, if no deal can be made, there would be no 21-month transition period, which U.K. Prime Minister Theresa May is now proposing. If that is the case, the U.K. would have to leave the EU before the deadline and all previous associations set up in the past four decades would come to an end abruptly.

From the economic perspective, maintaining close cooperation is essential for both sides even after Brexit because economic relations sit at the core of all their partnerships.

However, tariffs, customs and some other regulatory issues caused by the no-deal and unhappy divorce will severely hurt bilateral trade. Not only business, consumers, investors and public bodies will also be negatively influenced, thus bringing uncertainty to life, employment, investment, public safety and financial stability in Britain.