England captain Andrew Strauss has entered the debate over the controversial omission of Kevin Pietersen from this week’s third Test, saying he regrets “dirty laundry” being aired in public.

Last weekend, Pietersen was dramatically dropped from England’s squad, despite scoring a superb 149 in the second Test at Headingley, after failing to reveal the contents of text messages allegedly sent to South African players during that match.

Some of those texts are said to include derogatory comments about Strauss and England coach Andy Flower.

Pietersen’s inability to either say whether the messages were true, or indeed apologise for them if they were, led England to omit him from the third Test that starts at Lord’s on Thursday.

It is a game England, 1-0 down in the three-match series, must win if they are to prevent South Africa replacing them as the world’s number one Test side.

The match also marks Strauss’s 100th Test and his 50th as captain, with the fixture taking place on his Middlesex home ground.

In an interview with Sky Sports on Tuesday, Strauss insisted he’d always had good relations with Pietersen, his predecessor as England captain.

“I’ve always got on with Kevin,” he said. “I’ve tried to be honest with him; he’s been honest with me.

“That’s why this has all been a bit of a surprise to me,” Strauss said.

“I think the discontent that Kevin had with the board over his contract situation was one that the players didn’t get involved in – and I didn’t really get involved in, if I’m honest.

“But over the last week I have had to get involved, because there have been issues a little bit more central to his relationship with the other players and our ability to perform out in the middle.”

Strauss’s management partnership with Flower has been behind much of England’s success in recent years and the opening batsman added: “Firstly, I’m a big believer in not airing dirty laundry in public.

“It’s one of our core values in our team that what goes on in the dressing room stays in the dressing room.

“Any time anyone has fallen foul of that they have been disciplined – and rightly so.

“It’s about mutual respect and trust, and that is a core issue that is central to resolving this.”