A while back, I stumbled upon something interesting in a collection of documents from John Major’s premiership. It’s a brief letter from Roderic Lyne, Major’s Private Secretary, to Sir Robert Fellowes, the Queen’s Private Secretary, seeking permission for Major to be absent from the UK in order to visit the USA.
There is a longstanding custom in the UK that Cabinet ministers must seek the Sovereign’s permission before leaving the country, though there are no legal penalties for failing to do so. In 1883, William Gladstone took a cruise around the Hebrides that morphed into a visit to Scandinavia, and Queen Victoria took him to task for leaving the country without her permission. But other than Victoria’s ire (which he was used to by that point!), Gladstone wasn’t punished for his actions.
Although there are no penalties for failing to obtain permission, it seems to be something that’s taken seriously. When a European Council meeting threatened to keep Major out of the UK beyond the time for which he’d received the Queen’s permission, Downing Street contacted the Palace to obtain an extension.
As far as I’m aware, this convention is still in force today, though it’s hard to say with any certainty. Prior to 2007, the Ministerial Code and its predecessor, Questions of Procedure for Ministers, explicitly mentioned the need to seek the Queen’s permission for foreign travel.
That language disappears from the 2007 Code onward, but that isn’t necessarily proof that the custom has ended. The nature of the Code itself has changed. It’s now more streamlined with a focus on information that’s relevant to all ministers. The section on ministerial travel is far more concise than it used to be, and language about seeking the Queen’s permission isn’t the only thing that has disappeared. Recent Codes don’t say anything about Cabinet ministers needing to seek the Prime Minister’s permission for foreign travel, yet that is still very much the case even today.
It’s also not clear why the custom would have been abolished. Customs are abandoned from time to time, but there’s usually a practical reason for doing so. For example, King George VI abolished the practice of having the Home Secretary attend royal births once he realized that representatives of the Dominions would need to summoned as well, raising the prospect of seven government officials sitting outside the birthing room. Requiring a civil servant to dash off a brief letter to the Palace seems unlikely to cause enough inconvenience that the Government would insist on abrogating the custom, and it’s hard to imagine the Palace pushing to end it either. So, in the absence of clear evidence to the contrary, it seems safe to assume that the convention remains in force today.
 Junior ministers aren’t required to do this, however.
 Roy Jenkins, Gladstone: A Biography (New York: Random House Trade Paperbacks, 2002), 487.
 Rodney Brazier, Ministers of the Crown (Oxford: Clarendon Press, 1997), 101 n. 95.
 It might also be worth remembering that, if Major’s visit to America is any indication, responsibility for obtaining the Queen’s permission falls to ministers’ staff rather than ministers themselves. This could just be another routine thing that civil servants handle when arranging for ministerial travel.
 Jane Dismore, Princess: The Early Life of Queen Elizabeth II, (Guilford: The Rowan & Littlefield Publishing Group, Inc., 2018), 245.