The 23-year-old utility player was on loan at Rangers last season from Liverpool, who released him earlier this summer.

The Scottish champions were keen to retain him permanently but Vignal rejected their offer in favour of a return to England with Pompey.

Chairman Milan Mandaric told the club's website, www.pompeyfc.co.uk: "We are very pleased that another quality signing is set to join the club and who can be an asset to us in a number of positions.

“He has shown his worth at Rangers last season and the competition for places at Pompey will be that much healthier.”

Vignal, who can play at full-back or in midfield, cost Liverpool £500,000 from Montpellier but was also sent on loan to Espanyol and Rennes before a season-long loan at Ibrox.

Portsmouth chief executive Peter Storrie said: “Gregory is a versatile player who can play in a number of positions.

“When his chance came at Rangers he showed what a fine all-round player he is and though he is a defender he likes to get forward.

“He is the sort of player who will fit in well.”