The Northern Ireland midfielder remained in Glasgow to finalise the formalities of the switch following his country's goalless draw with Scotland at Hampden Park.

Davis, 23, spent the second half of last season on loan at Ibrox and has been a target of manager Walter Smith all summer.

Davis helped the Glasgow giants win two domestic cup competitions last season as they came close to winning an incredible quadruple.

He is Smith's fourth midfield signing in little over a week following the arrivals of Aaron Niguez Esclapez, Pedro Mendes and Maurice Edu.

Davis, who did not play in Fulham's opening Barclays Premier League match at Hull City, could make his second debut for Rangers in Saturday's match at Aberdeen.

Northern Ireland team-mate David Healy backed Davis to be a huge success at Ibrox.

He said: "It's a great boost for the lad. He went up last year and I know he did terrifically well.

"Rangers think a lot of him, they wouldn't be spending the money they are spending on a player who they don't think is going to improve them.

"He is a quality player, he proved last night his energy levels are there, his fitness is there, and his desire to get in the box.

"He put in two or three balls into the box, which if we play with a 4-4-2 he sometimes doesn't get the opportunity to break into the box.

"Rangers are getting a good signing, that's for sure, and someone who is going to keep on improving and improving."