Queen Becomes Britain's Longest-Serving Monarch

The Queen has thanked those who have sent her messages of kindness on the day she became the UK's longest-serving monarch.

Her Majesty made a short speech acknowledging the milestone as she opened a new railway in Scotland, on what the Royal Family describe as a day like any other.

The Queen broke the record previously held by her great-great-grandmother Queen Victoria whose reign, according to Buckingham Palace, lasted for 23,226 days, 16 hours and 23 minutes - or around 63 years and 216 days.

The milestone was passed at about 5.30pm this afternoon - but it was difficult to pinpoint a precise time because the exact moment of her father's death is not known.

Earlier in the day, she arrived in Tweedbank station after spending the last few hours travelling on a steam train on the newly opened £294m Borders Railway, and spoke to hundreds of people who had turned out to see her unveil a plaque.

Among those who accompanied her on the railway journey from the Scottish capital were the Duke of Edinburgh and the First Minister of Scotland Nicola Sturgeon.

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She thanked those who gathered at the station to welcome help her celebrate the day, including many schoolchildren.

She said: "Prince Philip and I are very grateful for the warmth of your welcome on this occasion.

"Many ... have kindly noted another significance attaching to today, although it is not one to which I have ever aspired.

"Inevitably, a long life can pass by many milestones. My own is no exception.

"But I thank you all, and the many others at home and overseas, for your touching messages of great kindness."

Earlier, the Prime Minister was among those who paid tribute to the Queen.

David Cameron said: "Over the last 63 years, Her Majesty has been a rock of stability in a world of constant change."

Speaking at Tweedbank Station ahead of the Queen, Ms Sturgeon also paid tribute to the monarch.

She said: "We are privileged ma'am that you have chosen to mark today's milestone here. All of us are delighted to be able to share some of this special day with you.

"For those watching from around the world let me say, on their behalf ma'am a simple but heartfelt thank you."

Google was among those to mark the event with a line at the bottom of its homepage saying: "Congratulations Ma'am."

The Queen went on to meet railway workers at Tweedbank as Philip trailed behind taking a quick look at the steam locomotive they travelled on.

There are not any large scale national events planned to mark this milestone, and members of her family will not be seen to celebrate the moment.

The Queen herself had said she didn't want any fuss, and expected it to be business as usual, treating the day as a normal one.

It is understood this was partly out of respect for Queen Victoria, but also because large celebrations are being planned for Her Majesty's 90th birthday next year.

It comes as a Sky News poll suggests the monarchy and the Queen remain as popular as ever.

The results from Sky Data found that 70% of people think Britain should remain a monarchy forever, with 61% saying they did not think the monarchy was a waste of money.

Some 58% also said they trusted the Queen more than most politicians. Some 1,117 Sky customers were questioned with data weighted to match the profile of the UK population.

A new photograph of the Queen was also released by Buckingham Palace for the occasion.

:: Sky Data interviewed a nationally representative sample of 1,117 Sky customers online from 21-24 August this year. Data weighted to match the profile of the population.