Having lost against France on Sunday, Emgland face Switzerland in a must-win match on Thursday before concluding the group stage against Croatia on Monday. Switzerland drew 0-0 with Croatia in their opener.
Robbie knows all about the threat posed by the Swiss, who overcame the Republic of Ireland twice during Group 10 qualification - winning 2-1 in Dublin and 2-0 in Basle. The striker insists they are not a side to be underestimated.
"They are a tough side and did well against us in the two games - it is going to be a difficult game for England," said Robbie.
"When you are playing in championship games - I don't care what anybody says - in that environment there are no easy games. It is going to be a tough game for England and I just hope that people don't expect them to walk all over Switzerland. It is going to be a lot harder than that."
Switzerland might not possess the most instantly recognisable individuals in the tournament, but Robbie points out that they do perform as a very effective team.
"If you tried to compare them with a Premiership equivalent they would be a bit like Charlton. They really work hard for each other, there aren't really any superstar players, but they have got a unit that works for them."
Robbie Keane has warned England not to write off the challenge of the Swiss.