brussels prime minister theresa may say would tell fellow european union leaders thursday ambitious plan progress brexit negotiations come weeks arrive summit brussels tell reporters ... look concrete progress make exit negotiations set ambitious plan weeks ahead particularly example want see urgency reach agreement citizens right say would also pledge continue british cooperation eu areas security defence set weeks ago florence bold ambitious agenda vision future partnership eu uk heart remain cooperation key issue deal share challenge face speech ... set ambitious vision look forward us able progress weeks ahead may call brexit talk progress eu summit