Why indeed? But to answer this question, we need to, first of all, look back at the original film series.
Let's consider A New Hope for a moment. Han Solo and Luke Skywalker were the action heroes of the movie and had American accents, while Moff Tarkin (played by Peter Cushing) and his crew wouldn't have sounded out of place in Downton Abbey.
But was this coincidence, or did it happen by design?
Maybe a bit of both. After all, the films were predominantly filmed at Elstree Studios in Borehamwood – a little town just to the north of London. As such – and remember here we're talking the mid-seventies and before anybody knew just how successful Star Wars would be – it seems apt that outside of the real heroes of the movie, producers would be limited to local available actors.
Of course, Andor was also filmed mostly in the UK – although I think it's fair to say with a significantly enhanced budget.
But surely location is not the sole reason for UK accents in Star Wars?
Of course not. For a start, Peter Cushing was a well-known actor and would have been specifically chosen for the part. Which brings us to the wider canon of US movies – where posh Brits are routinely portrayed as villains or incompetents.
These are people who speak what will now be known as the King's English but is correctly termed 'received pronunciation' (RP). This is a peculiar accent that derives from nowhere but was instead created as part of the class system that still dominates life in Britain to this day – the type of voice you might traditionally associate with the BBC.
But perhaps more important than the British class system, when it comes to judging accents in Star Wars, is the fact that, let's face it, the series draws parallels with British rule of the US, the Boston Tea Party, and all that comes with it.
The Galactic Empire, whether consciously or unconsciously, represents the British Empire to some degree – and the rebels are the type of ragtag bunch of upstarts that we're now so familiar with following the success of Hamilton.
Naturally, with the accent roles having been determined by the original film trilogy, it stands to reason that these would remain consistent in any associated series like Andor.
So, the number of British accents in Andor is largely due to British history and how it connects with the emergence of America as a sovereign state.