Alastair Cook has insisted that it is important for England to keep their focus on South Africa following the saga involving Kevin Pietersen's omission from the Test squad.

Pietersen has apologised to the ECB for sending texts to South African players about captain Andrew Strauss, but the batsman's international future remains unclear.

However, Cook believes that England must quickly switch their attention to the third Test match at Lord's, a vital game for the world's number one ranked Test side.

The vice-captain told The Metro: "It's certainly taken a lot of the focus off the cricket but as a group of players we are determined to come out tomorrow and fight like we've never fought before to win this Test and maintain our status as the No.1 side in the world.

"One of the skills you need as an international cricketer is mental strength."

South Africa lead the series 1-0 heading into the final Test at Lord's beginning on Thursday morning.