With the 50 metres and 100m already in the bag, the 200m final was a thrilling clash between Benson and his University of Stirling clubmate, Ross Murdoch.
Murdoch will defend the title at the Commonwealth Games on Australia’s Gold Coast in April, but it was Benson who took the glory in Edinburgh last night.
Trailing on the penultimate length, the two-time Olympian produced a great final turn and pulled away to win in 2:06.66.
Murdoch, who will compete for GB at the European Short Course Championships in Copenhagen this week, touched in 2:07.20.
Corrie Scott (University of Edinburgh) also completed a hat-trick of breaststroke titles, holding off the challenge from Hannah Miley to win the 200m in 2:24.48.
But Miley was in a class of her own in her favourite 400m individual medley. The Commonwealth Games champion won the gold by almost eight seconds in 4:34.69.
Orla Adams, also coached by Miley’s dad, Patrick, with the relatively new Aberdeen Performance squad, was second.
In the men’s 400 medley, Dan Wallace, who was disciplined after having been fined for drink-driving, showed he is ready to knuckle down and get back to his best.
The 2014 Commonwealth Games champion, who is now training with Edinburgh University, won the 100m butterfly on Friday and a 4:13.31 swim secured a second gold.
Duncan Scott, the double Olympic relay medallist, will join Murdoch on the plane for the Europeans in Denmark starting on Wednesday, and won the 200m individual medley in a fine 1:55.85.
The 20-year-old University of Stirling youngster was happy with his preparation.
“It’s up there with the fastest time I’ve done,” he said. “I’m looking forward to getting out to Copenhagen. It’s my first senior European Short Course so I’m just going in there to do my best. At the Championships, you always get some people you’ve never heard of swimming ridiculously fast.
“I’m going to be doing a lot of events but it’s a chance to get out there and try and swim some good times. I know I’m in solid shape.”
Craig McNally has not had it easy over the past few years. He just missed out on the 2012 Olympics, was ill during the 2014 Commonwealth Games and failed to make the Rio 2016 team. But the City of Glasgow swimmer confirmed he is still Scotland’s outstanding backstroke man, winning all three titles. He rounded off the hat-trick by taking the 100m in 52.95. Stephen Milne finished second – minutes earlier the experienced Perth City swimmer had pocketed gold in the 200m freestyle.