LONDON (AFP) - Luke Shaw proclaimed himself to be a Manchester United player on Friday, in apparent confirmation that the teenage England left-back had moved from Premier League rivals Southampton in a deal worth a reported £30 million (S$64 million).

Although there was, as yet, no official word from either club, the biography on Shaw's Twitter account now read: "Professional footballer at Manchester United Football Club."

Shaw's arrival at Old Trafford, if confirmed by United, would come a day after the English giants completed their first signing since Louis van Gaal, currently coaching the Netherlands at the World Cup, became their manager and would take the club's spending to nearly £60 million in two days after midfielder Ander Herrera joined from Athletic Bilbao for a reported £28.5 million on Thursday.

The 18-year-old Shaw made his World Cup debut in a goal-less draw against Costa Rica on Tuesday - England's last match of Brazil 2014 after defeats by Italy and Uruguay meant they could not get advance from their group.

He was a key figure in a promising Southampton side who finished eighth to United's seventh in last season's Premier League table.

But that team appears to be unravelling.

England striker Rickie Lambert has already left for Liverpool, with midfielder Adam Lallana, his club and international team-mate, poised to do likewise.

While eighth place was considered an impressive finish for a club of Southampton's stature, seventh was unacceptable for United, who started the season as champions of England but ended the campaign having failed to qualify for both the European Champions League and the second-string Europa League as well.

Indeed, once Champions League qualification was no longer a mathematical possibility, United sacked David Moyes - retired managerial great Alex Ferguson's chosen successor at Old Trafford - and briefly installed club legend Ryan Giggs as caretaker boss before appointing the experienced van Gaal.

United great Paul Scholes has been critical of the proposed cost of Shaw's transfer, saying it exemplifies much that is wrong with English football.

"The proposed £34 million transfer for Luke Shaw to United is another example of something which has a bad long-term impact," he said in a blog for bookmakers Paddy Power.

"Clubs are priced out of this market which is why they go abroad for cheap options. For a left-back to be worth £34 million shows how silly the game has gone."