Bryan Robson has pinpointed England's defence as the Achilles heel of Sven-Goran Eriksson's team.
The former England captain believes inexperience and a lack of defensive depth could hinder Eriksson's chances in Korea and Japan in the summer
This will be the first World Cup for two of England's key defenders Rio Ferdinand and Ashley Cole.
And both those two, along with Sol Campbell, have suffered recent injury problems.
"I'm worried about
injuries to the defence because we don't have strength in depth in that area," said Robson, speaking at the Soccerex conference in Dubai.
"The injuries have been a hindrance. You just hope that Campbell, Ferdinand and Cole all go and they're fit and they're not rusty."
It will only be during the tournament that Eriksson will discover whether his relatively inexperienced squad will be able to cope with the pressures of a major tournament.
"We'll find out a lot about some of the younger ones like Kieron Dyer and Rio
Ferdinand," said Robson.
"It will be a big testing ground for five or six of them.
different attitudes. I always rose to the challenge to see if I was a better
player than my opponent.
"Some players can handle it but others freeze."
Robson believes that Mick McCarthy's Republic of Ireland squad could go
further than many expect.
"There's not the same hype around them as there is with England and
there's a lot of energy about the team.
"I think they could do very well."