Although 32-year-old Pietersen issued a carefully worded apology after the scandal broke last week, he has been warned he will not even be considered for England duties again unless he divulges the full content of all the texts.
A source close to the England dressing room said: 'If he refuses to show the contents of the texts then he's finished and if he does show the texts then he's probably finished anyway.'
Pietersen is understood to have sent the messages to South African stars AB de Villiers and Dale Steyn during the second drawn Test in Leeds that culminated in a press conference in which Pietersen highlighted divisions within the dressing room.
He later described the text as 'banter between close friends', but Strauss admitted he felt 'let down' by his highest profile player.
In a further embarrassment, it has also become clear that Pietersen spent the Monday night of England's defeat in the first Test in a London wine bar close to his Chelsea home with members of the victorious South African team.
While his own team-mates licked their wounds, he was spotted in Brinkley's, a favourite haunt of Chelsea players - including his friend Frank Lampard - alongside Steyn and de Villiers and a handful of others.
Despite his impressive batting average of just under 50, which puts him among the elite of world cricket, Pietersen has been a divisive influence in the dressing room because of his almost rock-star status in a traditionally understated sport.
Married to former Liberty X singer Jessica Taylor, the brash batsman shocked traditionalists early in his career by sporting an ear-ring and dying his hair. He also has a tattoo of the England badge on his arm.
Tensions between the batsman and the England management have been especially acute after cricket chiefs refused his demands that he be allowed to pick and choose his Test and one-day appearances so he could accept a contract worth more than £1.5?million to appear in the Indian Premier League.
Pietersen's fall from grace has overshadowed the deciding third Test, which yesterday saw England facing a struggle despite his replacement Jonny Bairstow making 95. The series is seen as crucial because the winners will be regarded as the world's number one side.
The Mail on Sunday has also learned the source of the original texts leak is a member of the official South Africa tour party, despite denials. On Wednesday the tourists' captain Graeme Smith said claims that the existence of the texts had been deliberately made public were a 'load of rubbish'.
Last night the England camp said it had no further comment and Pietersen's spokeman could not be reached.
Pietersen left South Africa in 2000 aged 20. Strauss, by contrast, moved to England with his parents at the age of six and was educated at Caldicott and Radley private schools.
- DAILY MAIL
