Mark Darcy from Bridget Jones’s Diary is not to be confused with Fitzwilliam Darcy from Pride and Prejudice – they have both been played by Colin Firth.
The answer to this esoteric question comes back to the work of Renaissance man Nicholas Barbon. Amongst his various pursuits, Barbon was a major property developer in London. In particular, he was responsible for the development of Red Lion Square, near Holborn. (For some, “Red Lion” will sound familiar – BPP Holborn is nearby on Red Lion Street.)
Red Lion Square had a fascinating history before its association with Barbon: it was named after the local pub, Red Lion (Lyon) Inn, and is an alleged resting place for Oliver Cromwell. In addition to being “one of the oldest and smallest garden squares in Camden”, it may also be the “only London square that was built after a violent pitch battle”.
Barbon had a vision for developing Red Lion Fields into a new Red Lion Square. He wanted to “create a new square with greater exclusiveness and commercial return” – to have some spacious houses set around a central square, and to have some houses on the perimeter to screen out the hustle and bustle of High Holborn. This required demolition and rebuilding.
And this was something that the Gray’s Inn lawyers were not happy with. They neighboured the Red Lion Fields, and claimed that they would lose their “wholesome air” with Barbon’s development. As Barbon had legally bought the land that he planned to develop, the lawyers lost their case.
You would think that lawyers would respect the law or find some other way – using their great learning and way with words and so forth – to challenge that decision. Around 100 lawyers from Gray’s Inn armed themselves with bricks and other building sundry items. They then went at the workers on site. Apparently Barbon also got involved in leading his workers, and ultimately (with injuries on both sides) the lawyers lost. Barbon got his way.
There is something beautifully ironic in picturing 100 lawyers going at some poor builders with bricks after the lawyers had lost their case in court. It seems so discordant with the noble, upright imagery of dazzling oral advocacy. They were probably not very good at fighting – they lost both their case in court and on the field.
Bringing it back to Mark Darcy, this almost-comical image of lawyers engaging in some ineffectual fisticuffs is reminiscent of two great fights that he has with Hugh Grant’s Daniel Cleaver (the first involving apologies from both Darcy and Cleaver to the diners at a restaurant whose meals and birthdays they interrupt, the second involving a fountain and another great wet shirt scene from Colin Firth). Both are painfully awkward – as Firth puts it, “[t]he last time these two characters fought was probably when they were 7 years old in the school playground, so this fight will probably look exactly like that. And in the end, that’s what it was! It’s one of the most organic things ever committed to film”.
Thankfully, this kind of questionable machismo is not so much a feature of modern lawyering (with some exceptions). And all joking aside about the fighting that lay at the heart of Red Lion Square’s development, in 1974 Red Lion Square was the tragic scene of a National Front demonstration where a counter-protestor – Kevin Gately, a student from the University of Warwick – was killed.
There are a lot of red lions (and particularly red lion pubs) in London, but the one in Holborn near Red Lion Square sure is a special one.
 I never made it to the Old Red Lion pub on the corner of Red Lion Street, but spent more time in the Wetherspoons nearby – Penderel’s Oak. Magnus Carlsen also had a celebratory pint at Penderel’s Oak after his tense victory in the 2018 World Chess Championship match.
 I am having some semi-traumatic flashbacks to learning about rights of light and other easements. There is the Prescription Act 1832, where generally (subject to various caveats and differences for light) 20 years’ use is required – and after the 20-year period the law presumes the right has existed since time immemorial (which is… 1189?). However, from what I can make out of my messy lecture notes from back in the day, this 20-year rule was also part of the common law prior to 1832. Although I am not too sure on the timeline, presumably the blokes at Gray’s Inn had been there for more than 20 years? Not having seen a published judgment, I can only speculate. But perhaps there was difficulty in proving that there was a sufficiently definite right for an easement to arise, or in establishing that the Barbon’s development would actually affect any alleged right to wholesome air.
 Speaking of modern lawyers, there is another link between Mark Darcy and Gray’s Inn as well – Mark Muller, a consultant on the films and a human rights barrister (who it seems like was the inspiration for Mark Darcy, rather than Keir Starmer), previously had chambers on Gray’s Inn Square (but now seems to be associated with Doughty Street Chambers).
 Not that many historical accounts of Red Lion Square highlight this more (relatively) recent tragic death, although some do – for instance, this blog. On a separate note, this blogger also chronicles their (ongoing) attempt to walk every street in central London and mentions Red Lion Square in this post. A noble quest.