The United Kingdom left the European Union on Jan 31, the first country ever to have done so.

Prime Minister Boris Johnson says the UK has "crossed the Brexit finish line". It is to his credit that, despite resistance from Remainers－including the former governor and European Union commissioner Chris Patten, who, despite preaching democracy for Hong Kong, sought to thwart it in Britain－this has finally been achieved. Over three and a half years have elapsed since the country voted to leave in the 2016 referendum, and Johnson has fulfilled his pledge to "get Brexit done".

The UK has now entered into an 11-month transition period, ending on Dec 31.

In this time, there will be negotiations over the future partnership between the two sides, hopefully resulting in a free trade deal. However, an immediate benefit for the UK of its EU departure is that it can now develop its own independent trading arrangements around the world, negotiating free trade agreements with major economies, including China.

As China and other countries have found, it is difficult to negotiate free trade deals with the EU. Its procedures are bureaucratic and its outlook is protectionist, but in addition, everything has to be tailored to suit the diverse interests of its 28 member states.

Because of fears of Chinese competition, some EU stakeholders are seeking a tougher strategy on China, and the US is asking EU leaders to do all they can to contain China's development.

The US, however, is not getting everything its own way. Despite pressure, Johnson wisely decided recently to give China's telecom giant Huawei a role in the UK's 5G rollout plans.

China, with the world's second-largest economy, and Britain, with the fifth, have much to offer each other.

In 2018, Britain and China committed themselves to safeguarding multilateralism, and to an open world economy, underpinned by the World Trade Organization. The UK already trades with China on the WTO terms, and, post-Brexit, this relationship can be upgraded.

Premier Li Keqiang has emphasized China's readiness to promote Sino-British ties in various areas, including trade.

China, as a proponent of the international trading system, opposes protectionism. Through free trade agreements, it can not only integrate into the global economy, but also stimulate market reform at home. There is no reason why the UK, as a sovereign state once more, should not be China's natural partner going forward.

With its financial services, low-tax and low-regulation economy, Britain is a highly attractive investment opportunity for China. Chinese companies in the UK are thriving. According to consulting firm Grant Thornton, the largest 750 enjoyed an average growth rate of 11.6 percent, and a combined turnover of ￡68 billion ($88 billion) in 2018.

There are new opportunities on the post-Brexit horizon, from which Hong Kong can also benefit.

Hong Kong, of course, is not only a founding member of the WTO, but also has historic links with the UK, and they each play leading roles in the world economy.

They can collaborate more closely over the innovative industries of the future, while working together on the financing of infrastructure-projects, including the China-proposed Belt and Road Initiative and Britain's National Infrastructure Plan.

With their seafaring traditions, both places can mutually develop their maritime sectors, including arbitration and sustainability. The UK, moreover, is eager to build a financial technology partnership with Hong Kong, and they have much to offer their global partners.

In numerous areas, the UK is highly esteemed around the world, and its fundamentals are sound. Its basic values, world vision and can-do spirit can be just as successful in the future as in the past, if not more so. As Britain once again embraces its global destiny, much of its focus will be on China. With their historic links and close associations, the two countries can now, in the interests of both their peoples, lift their partnership to new levels, and the opportunity must be seized.

The author is a senior counsel, law professor and criminal justice analyst, and was previously the director of public prosecutions.