The Lancashire second XI coach and experienced local league professional has been drafted in by England coach David Lloyd to help combat the leg-spin threat of Shane Warne.
Sleep - who played 14 Tests for Australia between 1979 and 1989 - has spent two days at Edgbaston bowling his own brand of leg-spin to the England batsmen.
And while he believes the England batsmen have improved their technique, Sleep is still backing Mark Taylor's men to take the series.
He said: ``English batsmen do not see leg spin very often at all and they have obviously got better with practise.
``But Shane Warne is one of the best bowlers in the world and not to be taken lightly.
``John Crawley is probably the best player of leg-spin and Alec Stewart plays it reasonably well.
``The rest have a few minor technical problems.''
However, despite the meticulous preparation of the England camp, Warne may be cast in a supporting role until the later stages of the game on a seamer's wicket.
Sleep was joined at Edgbaston by promising 18-year-old Lancashire leg-spinner, Chris Schofield, and former Pakistan bowler Iqbal Sikander.
But he has no doubts where his new loyalties lie.
``I will probably get a lot of stick from the Aussies but I live here and work here now and this is my adopted country.
``David Lloyd gave me the opportunity to work at Lancashire and I would love to see England knock the Aussies over for his and Mike Atherton's sake.
``But I do not think they will!''