Carroll was left out of Liverpool's squad for their Europa League playoff tie at home to Hearts, instead travelling to London to undergo a medical and finalise the details of his loan move to promoted West Ham.

The 23-year-old was targeted by the Upton Park outfit earlier in the off-season, but the powerful centre-forward rejected those advances, holding out for a possible move back to Newcastle United.

New Liverpool manager Brendan Rodgers had previously told Carroll he was unlikely to be a major part of his plans upon taking over at Anfield.

And with Liverpool dropping their insistence on a commitment from West Ham to buy Carroll if they remain in the English Premier League next season, the move has now been revived and completed.

Earlier on Thursday, West Ham manager Sam Allardyce said he planned to bring one more player to the club before the end of the transfer window, to join newly signed Matt Jarvis, who moved from Wolves last week.

"At the very best I think one player will be joining us before the deadline tomorrow," Allardyce said.

"Hopefully we can achieve that and get a quality player who could add to the team and the squad and make an impact almost immediately."

Both Mark Noble and Carlton Cole have been linked with moves away from Upton Park but Allardyce said there have been no bids and the club would not be entertaining any.

"We've had no bids," he said.

"Would we welcome any bids? No."

Another player reported to be leaving the English Premier League new boys is Nicky Maynard, who scored for the club in their 2-0 League Cup win over Crewe on Tuesday.

Maynard only signed for West Ham in January from Bristol City.

"There's been some interest in Nicky but there has been nobody that has encouraged us to try to sell, that goes for all the players," he said.