Ever since Peter Schmeichel proved such a pivotal part of the all-conquering team of the 90s, wearing the Manchester United number one shirt has come with huge gloves to fill.

Arguably, it was not until Van der Sar's arrival from Fulham in 2005 that Ferguson found a worthy replacement for Schmeichel, but the Dutchman was 34 then and, although his performances have been of a consistently high standard, age has now caught up with him.

Ferguson's judgment in the transfer window has been mostly unerring but goalkeeper is the one position that the Scot has really struggled with.

Fabien Barthez was certainly talented but his decision making could be erratic to see the least, while the likes of Massimo Taibi, Andy Goram, Roy Carroll, Raimond van der Gouw and Ricardo Lopez were hardly runaway successes.

All of which means Ferguson will be determined to get the right man this time. Here, Press Association Sport looks at some of the leading candidates.

MAARTEN STEKELENBURG

Van der Sar's replacement with Holland and Ajax would be a fitting successor in that respect. A very solid keeper who at 28 should be at the peak of his career.

MANUEL NEUER

The Schalke keeper is only 24 but already has plenty of big-match experience in domestic and European football as well as with Germany, for whom he performed brilliantly at the World Cup. Modelled himself on Jens Lehmann.

DAVID DE GEA

The 20-year-old Atletico Madrid keeper is already attracting the attentions of Europe's big clubs. Ferguson has largely been reluctant to put his faith in young keepers but this may be his best chance to land De Gea.

HUGO LLORIS

France's number one could well fit the bill having gained plenty of Champions League experience with Lyon. The Ligue 1 giants, though, are likely to demand a large fee for the former Nice stopper.

IGOR AKINFEEV

Akinfeev has long been linked with a move to United but may have been surpassed in Ferguson's wishlist by the names above. The 24-year-old has been first choice for CSKA Moscow since 2003.

ANDERS LINDEGAARD

It is easy to forget Ferguson has already recruited a keeper this season having signed Lindegaard from Danish side Aalesund in November. The 26-year-old seems unlikely to be first choice, though, especially after Schmeichel said he was not ready to be a Premier League regular for United.