Eoin Morgan has defended England's analyst's use of real-time signals in their T20I series against South Africa, saying that it is "100% within the spirit of the game" and that there is "nothing untoward about it".

Nathan Leamon, who is the main analyst for England's white-ball teams, has placed two clipboards - one with a number on a sheet of paper, the other with a letter - on the dressing-room balcony to help Morgan in his decision-making throughout the series, which was highlighted by host broadcaster SuperSport during Tuesday's 3rd T20I.

While England had cleared their plan with match referee Andy Pycroft, the use of signals has attracted some criticism in the British press - most notably from Michael Vaughan, who wrote in his Daily Telegraph column that there was "absolutely no chance" he would have engaged with an analyst looking to send him information during a game in his time as captain.

"Captains are different," Morgan said on Thursday, the eve of the three-match ODI series which starts at Newlands, in response to the criticism. "You get captains that really enjoy the title, the power and the accolades that go with it, and then you have other captains that continue to be pushed and want to learn for the benefit of the team.

"For me, this is a system that we're going to use to try and help myself and the other leaders in the side, to take the emotion of the decision-making on the field and compare that to the hard data that is continuing to feed data into us, and the guys off the field."

It is understood that the signals referred to a suggestion as to who should bowl the next over and a possible field setting. For example, in the signal '2C', the '2' might have been a suggestion that Chris Jordan should bowl, with the 'C' referring to a field set for wide yorkers.

Morgan added that his plans had largely aligned with Leamon's suggestions throughout the series, and that he had no doubts as to the ethics of receiving live data from off the field.

"There weren't many decisions that varied: I think there were three in the first game, two in the second game, and a couple in the third. It's nice to know that the majority of the decisions that myself, Jos and the bowlers on the field were making actually replicate what we feel is right in the game.

"100%, [it's] within the spirit of the game. There's nothing untoward about it. It's about maximising information that we're taking in, and measuring it against things [like] coaches' recommendations, the data, what's going on. We're definitely going to continue with it, and give it enough of a sample size to see if it makes a difference to, or improves, our decision-making on the field or our performance."

While the focus on coded signals has sparked debate this week, it is nothing new for captains to receive information from support staff during games. The majority of T20 tournaments around the world feature mid-innings strategic time-outs, giving coaches an opportunity to interact with players on the field, while dating further back, messages have been passed on during drinks breaks or during a change of gloves.

Morgan, who has previously used small sheets of paper during games to help him with his plans, reiterated that the use of data and interaction with the dressing room have been constant features throughout his time as captain.

"There has always been constant communication - verbal or physical - from the changing room to us on the field to help improve my decisions as captain and Jos's decisions as vice-captain, to try and correlate the feeling of the flow of the game and what we think are the right decisions [with] the data that we've already researched coming into the game," he said.

"It's something we've used a lot pre-game, and are experimenting with during the game now in order to try and see if we can improve our performance on the field. We're always looking to improve our performance as a team, and certainly me as captain, I want to get the best out of our players in order to get the best out of our team."

Charl Langeveldt, South Africa's bowling coach, suggested that his side had been unaware that England were using signals until they were shown during the broadcast of the third T20I.

"We didn't know they were using it," he admitted. "A guy like Corrie [van Zyl] used to use it when he was coaching at the Knights. I don't know how it works. It's maybe something we can look into. Maybe it could be when you go to death bowling or when you start bowling certain balls to certain batsmen… I'm not sure what it's about."

Matt Roller is an assistant editor at ESPNcricinfo. He tweets at @mroller98