What is the red Budget Box: Why is Sunak carrying a red briefcase?

You could be forgiven for thinking the red briefcase - or box as it is known - is just a quirky style statement.

In fact, the red box has a significant history behind it and is a longstanding tradition in British politics.

The red box carried the Budget speech from No. 11 to the House of Commons and is often held up outside Downing Street by the Chancellor (Rishi Sunak, in this case) who will pose for many a picture.

The briefcase has been used for more than 150 years with the first box made for William Gladstone in 1860. 

William Gladstone (PA Media)

The wooden box lined with black satin and covered with scarlet leather is a sign of good value for money.

Gladstone's hardy box was still in use as late at 2011 with the exception of James Callaghan (Chancellor from 1964 until 67) and Gordon Brown (Chancellor from 1997 until 2007) who both had new cases commissioned.

Gladstone's original box was used by Alistair Darling until 2010 and George Osborne. 

But it know rests in the Cabinet War Rooms in London where it has been retired amid concerns around its fragility. 

A new box commissioned by the National Archives in 2011 has been used by more recent Chancellors. 

The box is used to deliver the new UK Budget which details how the government will be spending money.

Rishi Sunak will deliver the budget today at 12.30pm (PA Media)

But there have been a few mishaps over the years.

George Ward Hunt arrived at the Commons on Budget day in 1869 to find that he had left his speech at home.

The mishap is believed to have inspired the tradition in which the Chancellor holds up the box to the crowd when he leaves No.11.

When Norman Lamont, who was chancellor from 1990-93, held up his red box for photographers before one of his Budgets in the early 1990s, it contained only a bottle of Highland Park whisky, with the crucial statement instead carried by aide William Hague.

Norman Lamont presenting his budget red box containing a bottle of whisky, rather than his speech (PA Media)

But why did he swap such an important document for whiskey?

By tradition, the only occasion when a minister can drink alcohol is when delivering their Budget speech at the despatch box.

Gladstone drank sherry with a beaten egg and Benjamin Disraeli had brandy. Geoffrey Howe in the 1980s preferred gin and tonic and Kenneth Clarke whisky, but more recent chancellors have all drunk water.