Former Tottenham Hotspur and England centre-back Sol Campbell has warned against building Dele Alli up too high in the early stages of his career.
The 19-year-old has been one of the breakthrough stars of the Premier League this term, scoring seven goals and seeing his club form for Spurs rewarded with a senior international call-up.
Alli has been tipped to play a big part in England's Euro 2016 bid, but Campbell believes that players need to prove their quality year after year to establish themselves at the highest level.
"He does look a real prospect, but it is very early stages for him. I don't really want to know about a player until five or six years down the line and I can see their consistency," Campbell wrote on Sportlobster.
"Anyone can have a good season or two - I want to see five, 10, 15 years of quality from a player to be able to call him 'world class'. We have seen players light up this league before for two or three years and then drop off and fade away.
"I am not saying Dele Alli will do that, but he needs to keep going. Hopefully he has a good mentality that will allow him to have the same sort of career [Steven] Gerrard and [Frank] Lampard enjoyed in the Premier League. It would, of course, be great for England if he could."
Alli has already made four appearances for his country, scoring one goal.
