For a document as important as a white paper on Britain’s exit from the European Union, you might expect the i’s to be dotted and t’s to be crossed well-ahead of deadline.

But there is a telling clue on the government’s Brexit policy release that reveals ministers may have been making tweaks to the document late into the night.

The time and date stamp on the Government’s newly-released white paper shows the final version was signed off by the Prime Minister during the early hours of Thursday morning.

The white paper's time stamp is printed on the bottom right-hand corner of every page

Civil servants in the Department for Exiting the EU (DexEU) appear to have pulled an all-nighter in a bid to prepare the official policy document for release.

Printed in small font on the bottom of each of the white paper’s 77 pages is a date stamp showing 4.17am.

One political commentator, David Allen Green, who spotted the detail, said his thoughts were with the “exhausted” official at DexEU who sent the file to the printers.

Government publishes Brexit White Paper setting out plans for leaving EU

A spokesman at DexEu told The Independent the department did not wish to comment on the exact time of publication – or what may or may not have been amended at the eleventh hour.

But it is understood that government documents – especially those of a particularly sensitive nature - are not routinely dispatched for printing until the last moment to allow for “fine tuning” and to make sure the contents are correct.