Ashton axed as England trim squad
With the tournament due to get underway in September, Lancaster has to reduce his squad to a final 31-man group by August 31 and Ashton was the highest-profile casualty of his round of cuts.
Fellow wings Semesa Rokoduguni and Marland Yarde, centre Kyle Eastmond, scrumhalf Lee Dickson, flank Matt Kvesic and prop Matt Mullan have also been dropped.
As expected, Rugby League convert Sam Burgess remains in the squad, while Danny Cipriani also makes the cut alongside fellow flyhalves George Ford and Owen Farrell.
The changes reduce the number of players who will be returning to the squad's training camp to 39.
"It has been difficult to narrow down the squad as everyone has contributed and given their all," Lancaster said.
"But what I've said to those guys who are not coming back in on Sunday is that the door is not closed by any means.
"They are only an injury away and there is a lot of international rugby to be played this season, culminating in a three-Test tour to Australia."
The removal of Ashton, Yarde and Rokoduguni leaves England with only three wings left in contention with Anthony Watson, Jack Nowell and Jonny May the trio who will return to camp on Sunday.
England have their contingent of scrumhalves now that Dickson has gone, leaving Ben Youngs, Richard Wigglesworth and Danny Care on course to make the final cut.
Nick Easter, who Lancaster revealed earlier this week is behind his teammates in conditioning due to his injury problems, was thought to be among those most in danger of losing out.
But he has been retained while Ben Morgan seeks to prove his fitness after recovering from a broken leg.
"Overall we are in good shape. Both Nick Easter and Ben Morgan are now fit and we want to give them both opportunities to train fully and prove their form and fitness next week," Lancaster said.
"We had a great two-week camp in Denver where the entire squad worked extremely hard and were exceptional in the way they went about the training.
"That has continued this week and competition for places has been very intense."
England play the first of three warm-up games against France on August 15 at Twickenham, where the World Cup starts when Lancaster's side face Fiji on September 18.
Agence France-Presse
