The Royal train pulled into Hornbeam Park at 10am before the Royal couple were driven to the showground on Wetherby Road where they joined thousands of visitors and Yorkshire Agricultural Society members to celebrate the landmark 150th show.

The Royal couple, who last visited the event in 1977 as part of the Queen's Silver Jubilee, were welcomed by the society's president, Chris Hall, and the show's Honorary Director, Bill Cowling.

Christine Pearson came all the way from Canada to see the Queen. She has lived there for 40 years but was staying with her son and daughter-in-law and her grandchildren in Otley.

She said: "I didn't expect to see her today so it's a real treat to see her. I've never seen her before. I thought she looked smashing. It's such a special thing to see her."

Since the Queen's last visit the society has considered relocating to other sites, but has invested more than £12m on the 250-acre showground after deciding to stay in Harrogate.

During their visit the Queen, dressed in black patent court shoes with a gold trim, a royal blue hat with a pink ribbon and a matching three-quarter length jacket, and Duke will be told about the society's latest venture – a £5.1m Regional Agricultural Centre, including a farm shop and cafe, which is intended as a year-round showcase for the best of the region's produce.

The centre, which will include new offices for the society's staff and accommodation for other not-for-profit agricultural organisations, is being built on the southern edge of the showground off Railway Road.

The Queen and Duke will be told that it has been designed and is being built with many sustainable elements. Concrete excavated from a long disused railway siding has been crushed and reused for the foundations.

It will have a timber frame and sedum roof. Fleeces from 1,500 sheep will provide the insulation, the building will use underground heat sources and rainwater will be harvested as part of its green credentials. The centre is due to open next May.

Although it was raining when visitors left the Great Yorkshire Show last night, the weather for today is set to improve. It is forecast to be cloudy with sunny intervals with the temperature reaching 70 degrees Fahrenheit.