Invitation letter by President Donald Tusk to the members of the European Council

Tomorrow we will meet in the European Council. It will be a crucial moment for the unity of our Union and for the future of the United Kingdom's relations within Europe.

After my consultations in the last hours I have to state frankly: there is still no guarantee that we will reach an agreement. We differ on some political issues and I am fully aware that it will be difficult to overcome them. Therefore I urge you to remain constructive.

The negotiations are very advanced and we must make use of the momentum. There will not be a better time for a compromise. It is our unity that gives us strength and we must not lose this. It would be a defeat both for the UK and the European Union, but a geopolitical victory for those who seek to divide us.

We will work on the basis of the proposal that I put forward on the 2nd of February, with technical and legal clarifications which have been worked out by our Sherpas to be circulated today. But all the political issues will remain open for tomorrow. The objective has been clear from the start: to reach a legally binding and irreversible agreement which addresses UK concerns, while being satisfactory to all. At the same time we will not undermine our fundamental values. It is my goal to do the deal this week.

On choreography: after the traditional exchange of views with the President of the European Parliament, and the family photo, we will address the UK issue at our first working session on Thursday afternoon. This will be an opportunity for all members to state their positions and voice their concerns. Given that we are talking about a legally binding agreement, we will need time to assess all the necessary changes overnight and revert to the issue on Friday morning.

Over dinner, we will discuss the latest developments regarding migration. In December we agreed on a number of priorities to be addressed urgently. The detailed reports drawn up by the Dutch Presidency and the Commission show that the strategy we have put together is beginning to yield results but the progress achieved so far is not sufficient. I want us to keep up the pressure on all elements of the overall strategy. We should agree the conclusions at the end of the discussion. As the EU-Turkey Action Plan plays a crucial role in our strategy, I will meet PM Davutoglu beforehand to assess the progress and discuss speeding up the agreement so as to achieve a substantial and sustainable reduction of the number of illegal entries from Turkey into the EU.

We will meet on Friday morning in an informal session with a discussion on the United Kingdom. The President of the European Parliament will join us for the debate. The exact timing is still to be decided as we may need to meet for bilateral consultations. Once the final text is ready, we will resume the plenary session to adopt it formally.

Later we will turn to the situation in Syria and Libya, and adopt the remaining conclusions. Finally, we will endorse the euro area recommendations, under the revamped European Semester. I look forward to meeting you in Brussels tomorrow.