Campbell, who had an 11-year international career with England, says trying to qualify for Euro 2020 will be far harder challenge than their run to the World Cup semifinals.
"We have to be honest, although they did incredibly well to reach the semi-finals in Russia the draw was also incredibly kind to them," said Campbell.
"They didn't really meet a top team until Croatia. Hopefully, moving forward, they will have learned a lot from the Croatia game in terms of not switching off. But when you look at what France or Belgium had to do, would England have survived the same tests?
"For me now, it's all about a reality check and how they push on. We have the Nations League then the Euros. Sometimes in the Euros you meet harder teams and let's face it, the likes of Italy and Holland will have a point to prove."