Theresa May: Brexit the end of Britain making vast contributions to EU
UK Prime Minister Theresa MayReuters

United Kingdom's Prime Minister Theresa May on Thursday said that Britain and the United States have the opportunity to "lead together" again, play their part in global security and assert their leadership role. She also "welcomed" the idea of the rise of Asian economies like India.

Also read: Jeremy Corbyn calls on Theresa May to be 'very blunt' when meeting Donald Trump

"As we rediscover our confidence together, as you renew your nation just as we renew ours, we have the opportunity, indeed the responsibility, to renew the special relationship for this new age. We have the opportunity to lead together again because the world is passing through a period of change. And in response to that change, we can either be passive bystanders or we can take the opportunity once more to lead and to lead together," May said during her speech at Republic Retreat in Philadelphia.

"I believe it is in our national interest to do so. Because the world is increasingly marked by instability and threats that risk undermining our way of life and the very things that we hold dear. The end of the cold war did not give rise to a new world order. It did not herald the end of history. It did not lead to a new age of peace, prosperity and predictability in world affairs," she said.

May added that the end of the Cold War brought new freedom only for some citizens of central and eastern Europe. However, ancient ethnic, religious and national rivalries across the world, which were 'frozen through the decades of Cold War", returned.

The UK PM said that new challenges for the West have emerged now, particularly in the form of "radical Islamists as countries with little tradition of democracy, liberty and human rights, notably China and Russia, have grown more assertive in world affairs."

"The rise of the Asian economies — China, yes, but democratic allies like India too — is hugely welcomed. Billions are being lifted out of poverty and new markets for our industries are opening up. But these events, coming as they have at the same time as the financial crisis and its fallout, as well as a loss of confidence in the West following 9/11 and difficult military interventions in Iraq and Afghanistan, have led many to fear that in this century, we will experience the eclipse of the West," May said.

May said that the United States and the UK have a responsibility to lead because if they step back, other countries will step up, which she said is "bad for America, Britain, and the world".

"It is in our interests, those of Britain and America together, to stand strong together to defend our values, our interests, and the very ideas in which we believe. This cannot mean a return to the failed policies of the past. The days of Britain and America intervening in sovereign countries in an attempt to remake the world in our own image are over. But nor can we afford to stand idly by when the threat is real and when it is in our own interests to intervene," she said.

May is scheduled to meet US President Donald Trump for a meeting this week. The UK PM has said that she would talk about NATO, post-Brexit trade, and fighting terrorism during their meeting.