By Wayne Veysey| Chief Correspondent
Walcott brought an end to his contract saga last month by signing a three-and-a-half year deal that includes the option of another 12 months.
Goal.com understands that the agreement stipulates that the year’s extension has to be triggered by both parties at a specified date, believed to be around 18 months before it expires.
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The option will increase Walcott’s pay by 10 per cent from his current £90,000-a-week salary up to the £100,000-a-week figure he had originally requested before talks broke down last summer.
Walcott became the sixth young British star to agree new terms with Arsenal either side of the New Year, following in the footsteps of Jack Wilshere, Alex Oxlade-Chamberlain, Kieran Gibbs, Aaron Ramsey and Carl Jenkinson.
Walcott is the only one of the sextet not to sign a deal that runs until 2018, but sources have said that Arsenal are "comfortable" with the length of the England international’s agreement.
They believe it provides a degree of protection for the club if the 23-year-old does not maintain his outstanding form of the last few months, while the extension clause also supplies a financial carrot when the activation date nears.
Goal.com exclusively revealed on January 9 that Walcott had agreed the terms of a new deal with Arsenal at their London Colney training headquarters that would hike his pay by £30,000 a week.
The contract was officially announced nine days later to end a long-running saga that had threatened to end a spell at the club that began when Walcott was a 16-year-old.
Walcott is Arsenal’s leading goalscorer this season with 18 goals in all competitions, a record more notable for the fact he has started only 20 matches and was overlooked for a starting place between August and November after his contract talks had stalled.