Jenkinson trained with the Three Lions on Sunday prior to their departure for tonight's [Tuesday] World Cup qualifier with Poland.
However, having represented Finland at Under-21 level, there is some red tape that needs sorting before Jenkinson can commit his future to England.
That is what he wants to do though, and boss Roy Hodgson is keen to see the process completed quickly.
"He made it very clear he wanted to play for England," said Hodgson.
"We are now making overtures to FIFA to try and make certain we can have him as an England player."
The 20-year-old will still have the option of playing for either nation until he plays a competitive match.
But Hodgson insists he would not select anyone just to stop him from appearing for someone else.
"I don't want to trick him into playing for England for a few minutes just to 'block' him," said Hodgson.
"But he had to make a decision because we're very interested in him even if the competition is tougher to get him into the England team rather than the Finland team."
When he is eventually introduced, Jenkinson will be part of an England squad that is slowly changing shape under Hodgson's guidance.
Of their 23-man squad for the 2010 World Cup, only nine are in the present group.
Jack Wilshere, Phil Jones and Chris Smalling to name but three will be live candidates for future squads once they are clear from injury.
It is a far healthier situation than anyone could have imagined following that depressing last-16 hammering by Germany in Bloemfontein, when the future looked so bleak.
And one of the 'new boys' is Jenkinson's Arsenal team-mate Alex Oxlade-Chamberlain, who after being a surprise choice for Euro 2012, is now in the England squad on merit.
"Alex is a player with enormous potential and ability," said Hodgson.
"He came in as the joker in the pack and he's certainly cemented his position.
"Like a lot of our young players, he has to fight so hard to get into his club team but we're more than happy with him.
"He has to take every chance he gets with England because, internationally, there aren't that many games in a year."