The 21 year old has been one of the country’s most talked about midfield prospects and it is a coup for Forest manager Sean O’Driscoll to add him to his extensive recruitment drive.
Lansbury is the seventh permanent signing made by Forest since the Al Hasawi family’s takeover of the club in addition to the loan signings of Daniel Ayala and Sam Hutchinson.
Said Chairman Omar Al Hasawi: “Henri joins us as a young player with a rich pedigree and fits the bill perfectly as the kind of talented player that our manager Sean O’Driscoll is intent on bringing into the club.”
In the last two seasons Lansbury has spent lengthy loan spells with Norwich City and West Ham United and in both instances helped them win promotion from the Championship to the Premier League.
Before that he had gathered first team experience in a loan deal with Scunthorpe United in the 2008-09 season.
In addition to his Arsenal career, Lansbury has represented England at all levels up to Under 21, making 14 appearances for Stuart Pearce’s squad and scoring five goals.