BACKGROUND May's letter vows to keep "deep and special" EU ties after Brexit

London (dpa) - Prime Minister Theresa May promised Britain‘s cooperation in upholding Europe‘s post-Brexit prosperity in her letter to European Council President Donald Tusk on Wednesday.May said she wants to agree upon mutual protection for the rights of British and EU citizens as an "early priority."Following are edited highlights of the letter, including May‘s seven principles for the negotiations:"This letter sets out the approach of her majesty‘s government to the discussions we will have about the United Kingdom‘s departure from the European Union and about the deep and special partnership we hope to enjoy - as your closest friend and neighbour - with the European Union once we leave.We want to make sure that Europe remains strong and prosperous and is capable of projecting its values, leading in the world, and defending itself from security threats.We want the United Kingdom, through a new deep and special partnership with a strong European Union, to play its full part in achieving these goals.We therefore believe it is necessary to agree the terms of our future partnership alongside those of our withdrawal from the European Union.The government wants to approach our discussions with ambition, giving citizens and businesses in the United Kingdom and the European Union - and indeed from third countries around the world - as much certainty as possible, as early as possible.Proposed principles for our discussions:1. We should engage with one another constructively and respectfully, in a spirit of sincere cooperation; 2. We should always put our citizens first; 3. We should work towards securing a comprehensive agreement; 4. We should work together to minimize disruption and give as much certainty as possible; 5. In particular, we must pay attention to the UK‘s unique relationship with the Republic of Ireland and the importance of the peace process in Northern Ireland;6. We should begin technical talks on detailed policy areas as soon as possible, but we should prioritize the biggest challenges;7. We should continue to work together to advance and protect our shared European values.Perhaps now more than ever, the world needs the liberal, democratic values of Europe. We want to play our part to ensure that Europe remains strong and prosperous and able to lead in the world, projecting its values and defending itself from security threats.At a time when the growth of global trade is slowing and there are signs that protectionist instincts are on the rise in many parts of the world, Europe has a responsibility to stand up for free trade in the interest of all our citizens.Likewise, Europe‘s security is more fragile today than at any time since the end of the Cold War. Weakening our cooperation for the prosperity and protection of our citizens would be a costly mistake.We recognize that it will be a challenge to reach such a comprehensive agreement within the two-year period set out for withdrawal discussions in the [Lisbon] Treaty.The task before us is momentous, but it should not be beyond us.Together, I know we are capable of reaching an agreement about the UK‘s rights and obligations as a departing member state, while establishing a deep and special partnership that contributes towards the prosperity, security and global power of our continent."