Ashton will be without a host of players for the South African trip

Ashton, who has called up Ben Skirving as a replacement for Pete Buxton, has more than 30 players out through club commitments and injuries.

"Damage limitation and Brian Ashton don't sit together," the coach said.

"We are going to approach the Tests in a very positive way, and let's see what happens in the first Test."

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England leave for Johannesburg on Tuesday for the two Tests, on 26 May in Bloemfontein and on 2 June in Pretoria.

Players from Wasps, Leicester and Bath have not been considered because of their European finals commitments while another 10 are currently in the treatment room.

The Springboks, however, are healthy and riding high on confidence after two South African sides reached the final of the Super 14 for the first time.

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England and South Africa played two Tests last autumn with both teams winning one. They also meet in the pool stages of this year's World Cup.

"From a domestic point of view they've made big improvements this season, although it's difficult to gauge because of the absence of the top-line New Zealand players until halfway through the Super 14," Ashton said.

"South Africa on home soil is always a big challenge at any time and whatever squad you take - I am not in the slightest doubt that they have some really good players.

"I was out there 18 months ago doing some coaching with the Blue Bulls and am well aware of the calibre of the players they've got. I would think they are going to be knocking about at the top end when the World Cup comes around."

Jonny Wilkinson, one of just five players in the squad who were part of the 2003 World Cup-winning side, admitted the trip will be a tough one.

"We are going to be hauled out of our comfort zone, but we want to go to South Africa and attack the tour and be positive," he said.

"It is about sticking out our chests and being pro-active, rather than just hanging on in there."

Number eight Skirving, 23, has been called up for the tour after Buxton was ruled out with a dislocated thumb he sustained early in Gloucester's Premiership final defeat by Leicester on Saturday.

Buxton had his thumb repositioned on Monday night but Ashton said: "Although the prognosis is good, Pete won't be able to take a full part in preparation for the first Test."

Skirving, who has been promoted from the England Saxons Churchill Cup squad, has represented England at every level from U16 to U21 and made his England A debut in February 2006.

He has also played for England Sevens and has made 92 appearances for Saracens.

Revised England squad:
Forwards: Alex Brown (Gloucester), Matt Cairns (Saracens), Darren Crompton (Bristol), Nick Easter (Harlequins), Andy Hazell (Gloucester), Chris Jones (Sale), Magnus Lund (Sale), Mark Regan (Bristol), Pat Sanderson (Worcester), Dean Schofield (Sale), Ben Skirving (Saracens), Andy Titterrell (Sale), Stuart Turner (Sale), Roy Winters (Bristol), Nick Wood (Gloucester), Kevin Yates (Saracens).

Backs: Anthony Allen (Gloucester), Iain Balshaw (Gloucester), Mike Brown (Harlequins), Andy Farrell (Saracens), Toby Flood (Newcastle), Andy Gomarsall (Harlequins), Jamie Noon (Newcastle), Shaun Perry (Bristol), Jason Robinson (capt, Sale), Peter Richards (Gloucester), James Simpson-Daniel (Gloucester ), David Strettle (Harlequins), Mathew Tait (Newcastle), Jonny Wilkinson (Newcastle).