The event, a duel with Brazil's 2016-17 Formula E champion Lucas di Grassi with the pair taking turns in the same car, took place behind closed doors on Tuesday night on a 346 metre straight.
The record, witnessed by Reuters, was announced officially on Friday.
The 2.09km track, which has indoor and outdoor sections with cars racing through the building in the Docklands area, hosts the title-deciding final two rounds of the season on Saturday and Sunday.
The previous record for fastest speed achieved by a vehicle indoors was 165.20 kph (102.65mph) set by U.S. driver Leh Keen in a Porsche Taycan Turbo S sportscar at the New Orleans Convention Centre in 2021.
According to Guinness World Records, who had a smartly-dressed adjudicator on hand to oversee proceedings, the car must start and finish at a standstill with the attempt taking place entirely indoors.
NEOM McLaren driver Hughes, who had three practice runs before his record attempt, warmed up with a run of 214.80kph before further runs of 215.05 and 217.65 through the speed trap.
Mahindra rival Di Grassi then took over the same car, with changed tyres, and did practice runs of 216.87kph, 217.92 and 218.18. His record attempt was then clocked at 217.65kph.
Hughes said his runs, with the car screeching around an opening corner before powering down the straight and then braking hard, had felt very fast.
"I didn’t know if 218 was good or bad," the elated Briton told Reuters after watching Di Grassi ultimately fall short of his mark.
"Seeing all the numbers flash up every time, I was stressed. I was really stressed. I’m over the moon actually. More so than I thought I would be.
"I felt like I’ve never wanted anything more in my life than having a world record," he added. "It’s something I never thought I would have but it’s going straight on the CV."
The record was never in doubt with the GENBETA car used for the event featuring an enhanced battery power output of 400kW with all-wheel drive and softer iON Hankook tyres.
Formula E's regular Gen3 cars can reach speeds of more than 322kph (200mph).
"With the amount of G-Force involved with these different tyres and the four-wheel drive system it just felt like you could put all the power down," said Hughes.
"It feels a lot in the helmet. It’s probably the fastest acceleration car I’ve felt in my career."
Formula E's new CEO Jeff Dodds, who took over in May and has been outspoken already in comparing his series to Formula One, said the record attempt was much more than just a bit of fun before the racing starts.
"It’s all about showcasing the potential of what an electric racing car can do," he told Reuters.