The Taoiseach says Queen Elizabeth's visit to Ireland in 2011 'cemented the relationship' between the two nations.
Micheál Martin is in London today and has paid his respects at the Queen's coffin alongside the President Michael D Higgins.
Both the Taoiseach and President have also signed a book of condolence at the UK Foreign Office.
Micheál Martin says the Queen's trip to Ireland eleven years ago was an important moment for both countries:
"We all recall that historic visit in 2011, which in many ways cemented the relationship between our two countries in the modern era, almost the crowning event of a whole series of events prior to that in terms of peacebuilding reconciliation, leading to the Good Friday Agreement. I think that was the significance of that visit."