Tuilagi, the Tigers centre, has been called into England's World Cup training squad despite still being banned for punching Chris Ashton in the Aviva Premiership semi-final.
The 20-year-old apologised for losing his cool but many felt the five-week suspension, which ends on Thursday, was lenient for a three-punch combination which left Ashton requiring stitches.
Tuilagi, the youngest brother from the Samoan rugby dynasty, was the Premiership's discovery of the year and Flood believes he is ready to be chucked in at the deep end.
"He has been outstanding," said Flood. "You could throw him into a Test match tomorrow. He wouldn't let it affect him.
"He might make a couple of mistakes but he would also do some fantastic things. He is really dynamic in the back line.
"He has a good structure around him, his family has an incredible heritage in the game and he keeps himself to himself.
"He is a quiet young man and he has handled himself very well this season.
"The good thing is he is English so we don't need to worry about playing against him!"
Tuilagi's four elder brothers all played for Samoa but he has lived in Leicester since the age of 13 and committed his international future to England.
Last year was Tuilagi's breakthrough season in the Premiership but he also had to fight the prospect of deportation after it emerged he had first entered the country on a six-month holiday visa.
The local Leicester MP took up Tuilagi's case and he was eventually granted indefinite leave to remain in England - and in August he could well pull on a Test jersey for the first time.
At the end of a five-week training camp, England face Wales at home and away before manager Martin Johnson has to narrow his 45-man squad down to the final 30 for the World Cup.
Tuilagi is in line to make his England debut in one of those matches.
"The more involvement he has with the England set-up, the more confident he will get and the more knowledge he will get in terms of the game and emotional management," said Flood. "He is learning from guys who have 60 or 70 Tests and I have no doubt he will step up."
Johnson's squad announcement yesterday came accompanied with a warning aimed at Tuilagi and Delon Armitage, who has also found himself in disciplinary hot water this season.
Armitage was banned twice last season, once for clashing with a doping control officer and once for punching the Northampton fly-half Stephen Myler.
"We can't have guys getting suspended down there for events on or off the field," said Johnson. "We are in New Zealand. We all know what that is like, it is a goldfish bowl. And you are at the World Cup so you are in a goldfish bowl within a goldfish bowl. We need guys who are available to play."
Asked whether he had spoken directly to Tuilagi and Armitage, Johnson added: "It is an ongoing process. We don't need silly suspensions when we are over there because it puts us all under pressure."
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