"She long to reign over us" Queen Elizabeth II's official picture released on day her reign surpasses Queen Victoria's

• The photo shows the Queen working through one of her red boxes in the audience room at Buckingham Palace
• She wears a pink floral print dress by couturier Karl Ludwig that was last seen during a visit to Perth in 2011 
• Surrounding her are family photographs, including one of Prince Harry and another of her as a young girl
• The Queen will become the UK's longest reigning monarch at around 5.30pm today, surpassing Queen Victoria 

An official picture of the Queen still hard at work has been released to mark the day she becomes the longest reigning monarch in British history - overtaking Queen Victoria.

The photo shows her working her way through official correspondence at Buckingham Palace, seated in her private study which is dotted with framed snaps of her family, among them Prince Harry and the Queen Mother. 

The Queen, who will surpass Queen Victoria's record of 63 years and 216 days at around 5.30pm today, is wearing a favourite floral print dress by couturier Karl Ludwig that was last seen during a visit to Perth, Australia, in 2011. 

Record-breaking: The Queen pictured reading official documents (6) in the audience room at Buckingham Palace by Mary McCartney. The image shows the monarch seated at the same desk to appear in the James Bond clip filmed for the London 2012 Olympics (1) wearing a Karl Ludwig dress
worn to visit Perth during 2011's tour of Australia (5). She also wears triple strand of pearls and a pink sapphire and diamond brooch (2). Beside her is one of her trademark Launer London handbags (3) while surrounding her are family photographs (4).

Beside her is one of her trademark black patent 'Judy' handbags by British manufacturer Launer, while around her neck is a triple string of perfectly matched white pearls. She also wears a pink sapphire and diamond brooch.

The photograph was taken by Mary McCartney, the daughter of Beatles star Paul who famously sang of the Queen being 'a pretty nice girl' in the song Her Majesty which was released on the famous Abbey Road album 45 years ago.

According to royal sources, the official portrait was the 46-year-old's idea. 'Having grown up during the reign of Queen Elizabeth II it was a thrill to meet her and a very great privilege to take her photo on this historic occasion,' said McCartney.

'She is a truly inspirational person, a trailblazer and a beacon for womankind.'

The photograph, which was released to the media this morning, also shows the Queen's red leather box which is delivered to her every day regardless of where she happens to be.

It contains policy papers, Cabinet documents, Foreign Office telegrams, a daily summary of events in Parliament, letters and other State papers sent by her governments in the UK, Canada, Australia and New Zealand, among others, as well as from the Commonwealth. 

Official portrait: The Queen photographed by Mary McCartney at Buckingham Palace to mark her record-breaking reign 

No change: The new photo echoes another taken in the 1960s of the monarch conducting official business at Buckingham Palace

Looks familiar: The Queen wearing the same Karl Ludwig dress as she steps off a Royal Flight plane at Perth Airport 

Enjoying herself: The Queen meets well-wishers in Perth during her 2011 tour of the country with the Duke of Edinburgh

All of the papers have to be read and, where necessary, approved and signed. They are made by leather goods company Barrow and Gale and the Queen still uses the boxes made for her on her coronation. 

They have been refurbished over the years and while Government boxes bear the Royal cypher, only the monarch's box is embossed with the words 'The Queen'.

The ornate desk in the picture was featured in the opening ceremony of the London 2012 Olympics when the Queen starred alongside James Bond, played by Daniel Craig.

During the famous footage, 007 is ushered into a Buckingham Palace room where the Queen is quietly working at the desk decorated with family portraits that feature in the McCartney photograph - separate images of her parents George VI and the Queen Mother and another of her grandson the Duke of Cambridge.

Record: The Queen will surpass the record set by Queen Victoria at around 5.30pm today 

Sharing: Some of the Queen's red boxes are inherited from George VI, pictured here with his family at his coronation in 1937

First photo: The Queen's coronation took place on June 2, 1953. She has reigned for 23,226 days and counting

The Queen, who is currently on holiday at Balmoral Castle in Aberdeenshire, will mark the occasion by opening the new Scottish Borders Railway with the Duke of Edinburgh and will later enjoy a ride on the £294 million railway with Scotland's First Minister Nicola Sturgeon.

Elsewhere, tributes have begun to pour in for the Queen with Prime Minister David Cameron telling Cabinet colleagues yesterday that she has a 'remarkable record' and was 'a symbol of Britain's enduring spirit admired around the world'.

Members of her family will also be making public appearances, with the Duchess of Cornwall visiting the studios of ITV's This Morning and the Prince of Wales visiting Dumfries House which he saved for the nation by purchasing it in 2007. 

Celebrations will be held throughout the day, with church bells ringing out across the country and business in the House of Commons will be postponed for half an hour so MPs can pay tribute to the Queen.

The BT Tower will scroll the message 'Long May She Reign' and the royal rowbarge Gloriana will join a flotilla of boats in a procession down the River Thames.

Tower Bridge will lift as a mark of respect and, as the procession passes HMS Belfast, a four-gun salute will sound out and the Massey Shaw fireboat will shoot jets of water into the air. 

REVEALED: THE SECRET MESSAGE CONCEALED WITHIN THE QUEEN'S OFFICIAL RED BOX 

Barrow and Gale, the discreet London-based leather goods company which makes the Queen's red boxes and also supplies HM’s Government, has revealed the existence of a secret message within the monarch's.
The usually secretive company spoke exclusively to MailOnline and said the box made for George VI was found to contain a hidden missive when it was returned to them for refurbishment three years ago. 
‘The Queen is very careful with her money but it also means a great deal to her to use one that belonged to her late father, it offers a sense of continuity and link to the king,’ explained a spokesman.
‘The one you can see in the picture is one of a number that she inherited from her father that we were asked to refurbish around three years ago.
‘When we received it the boxes were, as you can imagine, in a hell of a state. It was something of a labour of love, which took place over several months, to restore them.
‘When we pulled the boxes apart to reveal the shells for the first time since they had been made for her own father’s coronation, we discovered that one of our craftsmen had inscribed in pencil a secret message to the Queen’s parents. It was barely legible but read: ‘God Bless And Keep Safe Their Majesties’.
‘Whether they, or indeed we, were meant to see it no-one will ever know. But it was very moving and when we relayed this to the Queen’s private office everyone was incredibly touched.
‘There was some kind of initial alongside the message but it was impossible to work out who it belonged to and has been left part of the mystery. It seems rather fitting, really, given how long it had remained a secret.’
The spokesman added: ‘We take great pride of being part of an aspect of history.’ 
Her Majesty's red boxes are handmade from from pine grown in colder climates to ensure durability and covered them with red ram's leather.