Michael D Higgins was welcomed by the Speaker of the Commons John Bercow before making a speech to members of both houses in the Royal Gallery at Westminster on Tuesday afternoon.The President said: "I am greatly honoured to be the first President of Ireland to address you in this distinguished Palace of Westminster."He went on to hail the transformation in relations between Britain and Ireland and said the two nations can take "immense pride" in the Northern Ireland peace process."I am conscious that I am in the company here of many distinguished parliamentarians who have made their own individual contributions to the journey we have travelled together," he said."I acknowledge them and I salute them, as I acknowledge and salute all those who have selflessly worked to build concord between our peoples."I celebrate our warm friendship and I look forward with confidence to a future in which that friendship can grow even more resolute and more productive."While Sinn Féin abstains from taking its seats at Westminster, three of the party's MPs - Paul Maskey, Pat Doherty and Michelle Gildernew - were in the audience for the speech, alongside Prime Minister David Cameron and Tánaiste Eamon Gilmore.Earlier Michael D Higgins and his wife Sabina met The Queen at Windsor Castle after greeting Prince Charles and the Duchess of Cornwall at the Irish Embassy in London.A standing ovation & lasting round of applause following President Higgins historic address to both UK Houses of Parliament #IrishStateVisit— Marc Mallett (@MarcMallett_UTV) April 8, 2014The President was honoured with two separate gun salutes before travelling with the monarch in a royal carriage for a state procession through the streets of the town, along a route decked out with Union flags and Irish Tricolours.The Queen then hosted a private lunch for Mr Higgins and his wife.On Tuesday afternoon Michael D Higgins laid a wreath at the Grave of the Unknown Warrior at Westminster Abbey, where he bowed his head in a mark of respect at a plaque in memory of the Queen's cousin Lord Mountbatten who was murdered by the IRA in 1979. He then visited the Houses of Parliament to give his address in the Royal Gallery.In the evening, The Queen gave a State Banquet for the President of Ireland at Windsor Castle, which was also be attended by the First Minister Peter Robinson and deputy First Minister Martin McGuinness.The presence of former IRA commander Mr McGuinness, who now represents Sinn Féin, has been regarded as a further significant milestone in Anglo-Irish relations.President Higgins and his wife Sabina touched down at London Heathrow on Monday afternoon accompanied by the Tánaiste Eamon Gilmore.They were met by the Viscount Henry Hood, Lord-in-Waiting, on behalf of The Queen. From there, they travelled to Windsor Castle where they will be based for the duration of their stay.President Higgins and his wife were issued the invitation to stay at Windsor Castle by the Monarch last year.