Britain's Queen Elizabeth began a two-day visit to Northern Ireland as part of a tour celebrating her Diamond Jubilee.

The Queen and the Duke of Edinburgh began a series of official engagements with a service of thanksgiving at St Macartin's Cathedral this morning.

Around 700 guests were invited to the Church of Ireland service, which was also attended by senior clergy from the four main churches.

Catholic Primate of All-Ireland Cardinal Seán Brady read a prayer, while the North's First Minister Peter Robinson gave a reading.

The Queen then visited St Michael's Catholic Church, where she met representatives from sporting bodies and business groups.

After leaving the church, the Queen went on a walkabout to meet dozens of local residents.

Later the Queen and Duke left in their motorcade for a private lunch at an undisclosed location.

It is Queen Elizabeth's 20th official engagement to Northern Ireland, but it is the first time a royal visit has been announced in advance.

The royals were delayed when their plane was unable to land at St Angelo Airport in Co Fermanagh this morning.

They were diverted to RAF Aldergrove, and flown to Enniskillen by helicopter.

Around 20,000 well-wishers are due to attend a garden party on the grounds of the Stormont estate tomorrow.

The Queen is due to meet Northern Ireland's Deputy First Minister Martin McGuinness at a function in Belfast tomorrow.

The Sinn Féin MLA has said that when he greets Queen Elizabeth he will be symbolically shaking the hand of every unionist in Northern Ireland.