Ashley Cole has retired from international football after being left out of England's World Cup squad - a decision Roy Hodgson admits was one of the hardest of his career.

The fight for the Three Lions' left-back berth has been one of the most interesting in the build-up to Monday's announcement of the 23-man squad heading to Brazil.

With Leighton Baines' place all-but certain, it was seen as a straight fight between 33-year-old Cole and Southampton teenager Luke Shaw - a battle the latter has almost certainly won.

The Chelsea full-back was informed on Sunday evening that he had not made the cut and, after collecting 107 caps, took to Twitter to announce his international retirement with immediate effect.

"I got the call from Roy and agree England team should be about the young players," Cole said via his account, @TheRealAC3. "I think it best I retire from England team now.

"We have a great manager and team and I wish them only success. I will be supporting them like a true fan. Thanks to everyone for everything.

#Baines and #shaw are great players, proved this season, and are the future of this country, it was a pleasure to get #107 caps #eng.

"Like me or not, trust me it's hurt me to stop playing for my country #proud and #honoured."

The timing of the information's leak is unlikely to please Hodgson, who names his 23-man party for South America on Monday at 2pm in Luton.

However, the England boss was quick to make a statement praising Cole and highlighting the difficulty of the decision.

"Among many difficult decisions I've had to make for my squad, not selecting Ashley was one of the hardest," Hodgson told

"He's been an incredible competitor for England, to amass over a century of caps is a truly staggering achievement and he deserves enormous credit for the desire and brilliance which has shone through over the years he has represented his country.

"There are few players who can be considered among the very best in the world, but Ashley in his prime was the best left-back without question."

He continued: "The most important factor was speaking to Ashley prior to the announcement on Monday, he deserved to hear it directly from me and he took the news with huge grace.

"In two years working with him he has shown nothing but relentless professionalism, and a great hunger to play for England. He is someone I have the utmost respect for and I wished him all the best, he in turn wished the team well this summer.

"Of course I must respect his decision to retire, he has been one of England's finest players, but I want to look to the future. It has been one of the hardest decisions of my career."

That decision shows enormous faith in 18-year-old Shaw, who Hodgson watched in Sunday's 1-1 draw between Southampton and Manchester United.

The Saints academy graduate's fine displays this term saw him voted into the PFA team of the year by his peers and handed his England debut against Denmark two months ago.

Cole - a player Shaw looked up to as a boyhood Chelsea fan - may not be the only big-name player to miss out on the 23-man squad, which is being announced at the home of England sponsor Vauxhall.

The pressure is mounting on Chelsea team-mate Frank Lampard, who has 103 caps to his name but could be hit by the emergence of Jordan Henderson and Ross Barkley.

Barkley, Shaw, Henderson and Liverpool teenager Raheem Sterling have breathed fresh optimism into England fans' hopes for Brazil, where Hodgson believes they can make an impact as well as gaining invaluable experience.

The former Fulham manager's defensive selection looks pretty straightforward, having said in March that his four centre-backs for the World Cup would be Gary Cahill, Phil Jagielka, Phil Jones and Chris Smalling.

Only if Jones is deemed unfit due to a recent shoulder problem will Everton teenager John Stones or Cardiff's Steven Caulker be called up, while Kyle Walker may miss out because of a pelvic problem which has kept him out for two months.

Midfielders Tom Cleverley and Michael Carrick are in danger of missing out due to their poor seasons with Manchester United.

Daniel Sturridge, Wayne Rooney and Danny Welbeck look set to be Hodgson's three main strikers.

Hodgson is a fan of Rickie Lambert, who is fighting it out with Andy Carroll for a fourth striker place. Jermain Defoe is sweating on his inclusion after swapping Tottenham for Toronto in March.

Joe Hart and Ben Foster are expected to be first and second-choice goalkeepers. John Ruddy, Fraser Forster and Jack Butland are vying for the third slot.

Hodgson will also name up to seven standby players, who will be drafted in should injuries occur in the warm-up camps in Portugal and Miami.