Project London aims to build a London-like city in GTA 5. Can't be hard, right? "I got a message the other day," says modder Kieran. "from some guy asking if the roads could be done—if the cars could be swapped to the opposite side in the style of British road networks. I sat down and calculated the work for that. I'm looking at 210 hours just for the roads."

The original GTA: London was set in the late '60s, but his version is inspired by the modern city. He aims to install landmarks incrementally, before building the project out into a pseudo interpretation of The Big Smoke. Kieran tells me that doing so involves a fair bit of Google Street-mapping, researching real life videos and photos, and a touch of artistic license. Even then, Project London is an ambitious undertaking.

"It's a lot of work, it will take time, but whenever I'm finished one thing—I've just finished Heathrow Airport, for example—I add it into the pack, update it, and release it. There are three of us working on it now, and while we strive to mirror reality, if we think something looks right in situ, and it still looks like London, then we're fine with that."

So far, this has seen Kieran—and partners Raddz Modding, ObsidianGames, Bleep999 and Albo1125—recreate Wembley Stadium, a handful of London Underground stations, a host of the city's major hospitals, and a range of British Emergency Service vehicles. Kieran tells me that the latter are worked on mostly by ObsidianGames, Bleep999 and Raddz Modding, and that vehicle models can cost upwards of £70 of their own money to implement. Next, the group has London hotels in their sights, real life billboards, bus stops, police stations. At some point they plan to remove the base game's iconic Vinewood hilltop sign "because, well, that's not London, is it?"

As a financial advisor for Lloyds Bank, finding time between life real commitments marks Kieran's biggest challenge. There are consecutive weeks where nothing gets done, he admits, but he hopes the recent formation of his three-person team can "keep the work flowing" into the future. His modding know-how is also self-taught and despite getting involved with GTA 5's British modding community less than a year ago, the standard of his work—not to mention his output—is impressive.

"Being part of various communities has made me realise that I've got an opportunity to do something," he tells me. "And that's where Project London started. Compared to other games, GTA is easier to mod, it's easy to get the files that you need in order to do work, and there are a lot of people who're able to offer advice and help out. That fact alone spurs you on to do more."

Despite being less familiar with Grand Theft Auto's first pre-millennium visit to Great Britain, Kieran tells me he became most involved with Rockstar's satirically swiping series via its faux Miami, Tommy Vercetti-starring Vice City. He says he's pored over every game since, but that GTA 5 marks his PC debut and thus the first of which he's modded.

"To be honest it was becoming aware of the modding communities that support Grand Theft Auto 5 that encouraged me to start doing the work I'm doing," he says. "Between [the three of us] we're trying to push forward and see what we can do, and achieve as much as we can achieve."

I think the standard, vanilla GTA is a bit lacking in certain areas, and that's why modders do what they do.

That's not to say Kieran doesn't appreciate the magnitude of the task at hand. As a hobbyist modder, his work is voluntary, part-time, and unpaid—and while he doesn't lack motivation, he's not yet in a position to even guess when the project might be finished.

"I genuinely couldn't tell you," he says. "There are just so many files that need opened, tinkered with, replaced. The whole thing costs me money too—there's a programme I need in order to do it. It's just a lot of work, there are so many files that need replaced across the whole map—you wouldn't believe the amount of files I've had to replace so far.

"Simply put, this project is something I love doing. It's something that I've always loved doing. I think it makes the game overall more enjoyable. I think the standard, vanilla GTA is a bit lacking in certain areas, and that's why modders do what they do."

While unable to commit to anything long-term, Project London is an exciting prospect. Following Grand Theft Auto 4's imitative New York City and its successor's artificial Los Angeles, a sizeable chunk of players have called for Vice City to take on real life Miami. I'd personally prefer the preconceived US trifecta eschewed in favour of something closer to home. And while I've no idea if Rockstar feel the same, Kieran and his team's efforts could go a long way towards satisfying my appetite.

No matter the timeframe, Project London is, for Kieran, strictly entertainment. I ask him if he'd ever consider a career in development off the back of something so ambitious.

"That's not something that particularly interests me, this is solely something that I like to do in my spare time. I love working with the GTA British community and working on something like this improves everyone's ideas for mods and what they wish the game could be like.

"I know there is a lot of us that wish we had a new GTA London and this project, ambitious as it is, goes a ways to realising that. There are a lot of us working to give the game a British-leaning look. We do a lot of hard work and I'm proud of that."

More information of the Project London work-in-progress mod can be found via its GTA 5 Mods page.