David Miliband, Britain's former foreign secretary, recently said the country had lost its influence after Brexit and was now just one of dozens of middle powers in the world.
Miliband, who is now head and chief executive of the International Rescue Committee, said that to reverse the decline the UK must create new foreign policy structures and make commitments to the EU.
He said: "Our relationship in NATO is strong, but we have almost no relationship with the European Union." Miliband also said Britain's decline could accelerate if Donald Trump is re-elected this year.
He believes that even if Joe Biden wins a second term, there are still warning signs about America's desire, patience and ability to provide active and sustained global strategic leadership.
As the Guardian reported, Meliband added: "In a world where the EU sends arms to Ukraine, it hosts six million Ukrainian refugees and is a major player in development, as well as being a member of the G20 and a regulatory superpower on trade, climate and information technology. This is digital sphere, we need to change our way of thinking. We must know that British policy towards Russia will be weaker and less effective outside the European Union. The same applies to China.
Therefore, Britain's decision in 2019 to abandon political and foreign policy relations with the EU should be reversed. Structures and commitments must be put in place to promote cooperation and coordination in the many common areas of foreign policy, defense, security and political development interests."
Miliband, who was foreign secretary from 2007 to 2010 under Tony Blair and Gordon Brown, says one of the illusions of Brexit was that Britain's fate depended on its own decisions rather than its ability to interact and bargain with other countries .
He said: "The Johnson government has demonstrated the danger that exists for British politicians: delusional thinking about England's power and position in a world dominated by rising global risks and powerful, astute, sophisticated, sometimes predatory countries and non-state actors who are growing. We must understand the realities of our government as it is today, and not as it was in the past.
We do not have the budget of Saudi Arabia, the anchor of the European Union in France, the regional activity and risk of Turkey, or the demographic power of India or Indonesia. We are one of many “middle powers” in the world system.
Our wealth, military assets and reputation relative to other countries have declined over the past decade. Our position on vital interests, from the economy to the climate crisis, national security and international development, will deteriorate unless we act. The reason is simple: the world is moving towards an unhealthy imbalance and the UK is on the wrong side of some key trends."