"We have this strong responsibility, collectively, to pass this message that yes, the European Union is not only still there but is going to be there more and more and more, and in an even stronger way in the coming months and years," Mogherini said.
Her speech came against the backdrop of the launch in June of her blueprint for the future of EU External Action, the Global Strategy, and following the result of the UK referendum.
"We are together the face and the voice of the European Union with our partners in the world – in our region and beyond our region. We know very well that in these months and in the year ahead we will need to reaffirm very strongly the EU's determination to play a very consistent, a very strong regional and global role and we are not looking inwards."
"The world is a dangerous place, and the only way in which we can invest in our own security and prosperity is if we work together with our partners in the world."
Mogherini also stressed the importance of better informing the EU's citizens of how important and influential the EU is in the world.
"Because the European Union is a key partner for peace, a key partner for stability, a key partner for economy, a key partner for many things, we have a long, long list. And sometimes my impression, it is a personal impression, is that our European citizens do not always see, do not always hear these messages coming from the outside on how important the European Union is for the world and for the stability of the world, which is also the interest of the Europeans."
She pointed to recent remarks by US President Barack Obama that the EU 'is one of the greatest political and economic achievements of modern times'.
The High Representative underlined that across the world, the EU plus its Member States is the world's first trading partner, first humanitarian and development donor, first foreign investor, first economic presence, first diplomatic presence, and sometimes the first security provider.
It was with this in mind, and the need to relaunch the European project, that Mogherini in June unveiled the Global Strategy. "Because exactly in the moment when people inside and outside Europe question the most whether the European Union is and will still be there, we need to say “yes” and to put on the table ideas on how we want to relaunch our role in the world and in our region."
She pledged to turn the vision in the Global Strategy into concrete action, with a roadmap for implementation with concrete timetables and steps.
This would include focused work on security and defence, an integrated approach to crises and conflicts, more internal/external coordination in EU external policy, and better follow-through on the numerous EU foreign policy strategies.
"And my message would be in a word, a mix of European pride and hunger for change, and ambition to realise this change, internally first of all," Mogherini concluded.
"No one of our Member States can exercise sovereignty effectively in the global world of today alone. While we can, if we want, if we act, together. So, we are much stronger than we realise. We have to use this strength, we have to pass the message of this strength, we have to foster it, we also have to change the things that prevent us from working more effectively. We have a lot to change, we have to make Europe an even stronger regional and global player and this is in the interest of our citizens and also in the interest of the rest of the world."