Britain needs to figure out what it wants before it goes into negotiations with the European Union (EU) in March, and learn from its past mistakes after Brexit, an expert said when commenting on Britain's departure from the EU Friday night.

Amelia Hadfield, head of Department of Politics and director of the Center for Britain and Europe at University of Surrey, told Xinhua in a recent interview that Britain needs to be clear when it goes into phase-one negotiations with the EU.

"Britain probably learned from their mistakes this time in terms of the sequencing of what they want, specifically the free trade agreement," the expert noted.

The moment that Britain officially left the EU also marked the start of a transition period that will last till the end of this year, in which Britain's trading relationship with the EU will remain the same and Britain will continue to follow the EU's rules and contribute to its budget.

"It's not solely free trade ... Probably the most important among them is gonna be security and defense protocols in order to be able to keep on both sides of the channel safe in terms of internal security," said Hadfield, specifically referring to agreements over customs with regards to goods.

The expert said Brexit's biggest impact on Britain would be the decline of its influence in the world. "For the most part, Britain is going to decouple from some of the largest policies, like development, like humanitarian aid."

But Hadfield said she believes that Britain would continue to lead in key institutions like the United Nations on the Security Council, and in specific areas like climate change as the country is hosting the UN Climate Change Conference (COP26) in Glasgow this year, the biggest global summit.

"It's gonna be a balancing act ... between trying to identify where Britain wants to be a leader, admitting there has been some reduction in terms," said the expert.

When talking about the idea of "Global Britain," Hadfield said it has been around for about 18 months as the Foreign Office has attempted to construct what it thinks Britain should be in the world, in security terms, in defense terms and in foreign affairs, which will have an impact on its special relationship with the United States.

"It's gonna be difficult for Britain to try to prioritize America at this point completely," she said. "I think there's also a sense that Britain is going to want to try to strike free trade deals in a sort of parallel way with the EU and also with the United States."

Hadfield noted that Britain has clearly got an eye on other global partners like China.

"Britain has always enjoyed a strong relationship with China in many ways," she said, as Chinese students, scholars and analysts have become "a huge part, a very successful enterprise and economy, and an educational structure" in the country.

"Britain needs to consider ways in which it wants to perhaps more fully engage with its Asian partners," the expert noted, adding that she can see "China certainly being and playing a very, very prominent role in that respect."

As for Britain's willingness to participate in the China-proposed Belt and Road Initiative (BRI) after Brexit, Hadfield said she believes that the BRI is a large-scale and ambitious initiative, and significant results in logistics and infrastructure construction have been achieved.

"I wouldn't say particularly in the short term, but perhaps as a five-to-10 year option, it certainly could be on the table (of Britain)," she added.