The fifth round of Brexit talks gets underway in Brussels today with a warning from the British Prime Minster that the ball is in the European Union‘s court.
In a speech to the British House of Commons, Theresa May is set to call for the EU to be flexible in its approach and promise the UK can get a deal that will prove the anti-Brexit "doomsayers" wrong.
She will call for talks to be approached in a constructive way “with our sights set firmly on the future.”
European leaders will decide at a European Council summit on 19-20 October whether “sufficient progress” has been made in the talks in order to begin negotiations on a future trading relationship.
"By approaching these negotiations in a constructive way - in a spirit of friendship and co-operation and with our sights firmly set on the future - I believe we can prove the doomsayers wrong,” Mrs May will say.
"I believe we can seize the opportunities of this defining moment in the history of our nation.
"A new, deep and special partnership between a sovereign United Kingdom and a strong and successful European Union is our ambition and our offer to our European friends.
"Achieving that partnership will require leadership and flexibility, not just from us but from our friends, the 27 nations of the EU.
"And as we look forward to the next stage, the ball is in their court. But I am optimistic we will receive a positive response.
"Because what we are seeking is not just the best possible deal for us - but also the best possible deal for our European friends too."
Mrs May's recent speech in Florence was welcomed by EU leaders as constructive - however, negotiators have called on the UK to introduce concrete proposals to back up the Prime Minister’s rhetoric.
Progress is needed on three key issues - the divorce bill, citizens' rights and the Irish border - before talks can move on to post-Brexit relationship issues, including trade.
European Commission president Jean-Claude Juncker said last month that it would take "miracles" for enough progress to have been made before the leaders' meeting.
Chief EU negotiator Michel Barnier meanwhile warned it could take several months for the key divorce issues to be decided.