New permanent England head coach Stuart Lancaster believes that the players must have the right motivation to succeed in this summer's three-Test series in South Africa.

The 42-year-old was officially appointed by the Rugby Football Union as the full-time coach today after leading England to four out of five wins in the Six Nations.

Lancaster's next challenge is the tour of South Africa, which is due to go ahead in June, and the former Leeds director has admitted that the 2015 World Cup is already in his sights.

"In terms of the South Africa tour, we saw with the British and Irish Lions what a challenging tour it is going to be," Lancaster said in a press conference. "The most telling point for me was that during the Six Nations, we started looking ahead to the summer and the players at that point knew they would be committed until the end of the South Africa tour.

"What happens between the domestic season finishing and the South Africa tour is critical in my mind. Players' motivation to go to South Africa has to be right. We have to get the mind-set right. There's a huge mental challenge going on that tour so that's going to be huge for us.

"It will get tougher for us, but if we want to be in a position to win in 2015 then we have to take on these challenges. We must want to go there and win. In terms of the development of this group, it will be a great benchmark for us."

Lancaster's new deal with England expires in 2016.