Princess Anne will officially open the Annandale Distillery and Visitor Centre this morning.
It's been closed for around 90 years, but is now producing single malt scotch whisky once again.
Princess Anne will then head to the International Sheepdog Trials near Moffat in the afternoon.
Watch as the Royal Train, carrying the Queen and Scottish First Minister Nicola Sturgeon, passes through the Scottish Borders.
It was an historic day for the Borders, as rail services officially returned to the region.
Watch the Queen's speech at Tweedbank Station, as she opened the new Borders Railway:
Queen Elizabeth, the UK's longest serving monarch, has thanked people in the Scottish Borders for welcoming her to the region.Read the full story ›
Scotland's First Minister introduced Queen Elizabeth, at the official opening of the new Borders Railway.Read the full story ›
Queen Elizabeth has arrived at Tweedbank Station.
She will unveil a plaque to officially open the new Borders Railway, alongside Nicola Sturgeon, the First Minister of Scotland.
She is expected to make a speech after the opening.
Crowds were out in force to welcome her.
Robin Bell, from Penrith, is a retired police inspector for Cumbria Constabulary.
In 1991 he was tasked with protecting the Queen on her visit to Penrith... and he ended up helping a young child, too.
All officers had a briefing by the Superintendent at the Police Station .and advised on the protocols of addressing embers of the Royal Family and that the Queen would take all the flowers from the children only in the front row.
I was assigned the right hand side of the forecourt of Mansion House as I was aware of some persons likely to be in the crowd who were well known anti-royalists and had photos of them..
The public were held behind steel crowd control barriers and the area was sealed off one hour before the Royal party arrived. I saw the Queen and the Duke walking through the gates of Mansion House then faced the crowd which included young children in the first line behind the barriers. I then herd the tap tap of high heeled shoes coming up behind me and then the Queen appeared at my side. She said “aren’t these flowers lovely officer” I responded “Yes your majesty”.
The party moved along and after a couple of minutes out of the corner of my eye to my left I saw a lot of sudden movements of the entourage and the Queen walked quickly towards me.
She said ”Officer there is a small child trapped behind the barriers, do something” I replied “Yes Marm” and saw a very small child with face against the barriers as the crowd surged forward.
I lifted out the child to the other side of the barrier and told it to stay there. When the Queen orders you to do something one must obey."
On a previous royal visit, in 1980, Robin cleaned the Royal car, and ended driving it back to where the Queen was staying:
Not many people can say I have sat in the Royal Limo."
The Queen has resumed her train journey to Tweedbank as she marks her historic day by inaugurating the new £294 million Scottish Borders Railway.
Prime Minister David Cameron has paid fulsome tribute to the Queen on the day she becomes Britain's longest running monarch, describing her reign as a "golden thread running through three post-war generations".
Speaking in the House of Commons, Mr Cameron said: "I do think it's right that today we should stop and take a moment as a nation to stop and mark this historic milestone."
Her Majesty the Queen inspires us all with her remarkable service, her dignified leadership and the extraordinary grace with which she carries out her duties.
It is truly humbling to comprehend the scale of service that Her Majesty the Queen has given this country. The reign of Queen Elizabeth II has been a golden thread running through three post-war generations.
The Queen is our Queen and we couldn't be more proud of her. She has served this country with unerring grace, dignity and decency. And long may she continue to do so.