Queen Elizabeth longest reign: Monarch shuns TV address but could mention record at Scottish Borders Railway

Queen Elizabeth is not expected to address the nation when she becomes Britain's longest reigning monarch but could mention the milestone when she officially opens the newly-built Scottish Borders Railway.

The Queen will officially reach the landmark at 5.30pm on Wednesday (9 September), 63 years and 217 days after her father King George VI died. Reports at the weekend suggest a wave of interest in the record could persuade the 89-year-old to address the nation.

But a Buckingham Palace source has told IBTimes UK that the palace was "surprised" by the news and confirmed it had not planned for her to make a televised speech. She will mark the occasion by sticking to her royal engagements and visit Edinburgh, Midlothian and Tweedbank to officially open the new railway along with the Duke of Edinburgh.

However, while a public address appears to have been ruled out, the source added the Queen could reference her record reign at the grand opening of the railway. The Queen is in Scotland ahead of her appearance at the railway's start line, where she will carry out an official opening on Wednesday. She will accompany Prince Philip on a steam train along the entire 30-mile route.

The landmark is said to be a "delicate issue" for Her Majesty as it also marks the anniversary of the death of her father, King George VI. Unofficial events that have been planned to commemorate the achievement include a repeat of the 2012 flotilla along the River Thames which marked her Diamond Jubilee.

From midday, historic vessels, leisure cruisers and passenger boats will sound their horns for one minute before sailing beneath the bridge on their way towards the Houses of Parliament. A new exhibition in Edinburgh will chart her years on the throne at Holyroodhouse. Entitled: Long To Reign Over Us, the exhibition, which has been curated by the Royal Collection Trust, will showcase the Queen through a selection of photographs from 1952 to the present day.

An official range of china, inspired by the design of the coronation programme, has been produced and a new £20 coin has gone into production. The limited-edition coin shows the Queen's five portraits that have featured on coins during her 63-year reign.