Custom Red Box | The British Parliament Boxes | The Wood Despatch Boxes | History from UK Parliament

Red boxes, or sometimes ministerial boxes, are a type of despatch boxes produced in England and are used by ministers in the British government and the British monarch to carry government documents. Similar in appearance to a briefcase, they are primarily used to hold and transport official departmental papers.
In the Chamber of each House there are two wooden boxes called despatch boxes. The despatch boxes are situated on either side of the Table and ministers and shadow ministers stand at the despatch boxes to speak. Despite their name, the despatch boxes are not used to contain documents or despatches but hold bibles and other items used when Members take the oath.

Despatch boxes were originally used by Members of Parliament to carry documents into the Commons Chamber. Two can now be found permanently in the Chamber on the central table and contain religious texts for the day of the Oath.
Frontbenchers (ministers and shadow ministers) deliver their addresses from their side's despatch box.
The despatch boxes in use today were gifts from New Zealand and designed by Sir Giles Gilbert Scott to replace the boxes destroyed in the Second World War bombings. Scott was able to base his design on the despatch boxes in the Australian Parliament. The Australian boxes were gifted to Australia by King George V in 1927 and based on A.W.N. Pugin’s original despatch boxes for the House of Commons.
The boxes are made from puriri wood which is native to New Zealand. The metalwork above the lock shows an entwined “GE” which stands for King George VI and his Queen, Elizabeth. Cast into the metalwork the words “The Gift of New Zealand” and the Latin words “Domine Dirige nos” meaning “Lord, guide us”. They were made by H.H. Martyn & Co. Ltd., of Cheltenham, England.
Despatch Boxes or 'Red Boxes', are a visible symbol of our democratic system ... Wherever in the world the Sovereign or Minister is, the Red Box is close by. ... also as being robust, sturdy, durable, reliable - the epitome of Britain's democracy.

According to HM Treasury:

Ministers are permitted to use ordinary lockable briefcases to transport information which has been classified 'Confidential' or below. For information with a higher security level (such as 'Secret') they are required to use dispatch boxes, which offer a higher level of security, and which are usually red. However, a travel version of the box is also available in black, which offers the same level of security as a red box, but is designed to be less conspicuous. In practice ministers use despatch boxes for transporting the majority of their documents due to the greater level of security they offer.