Manchester United are preparing an opening offer of initial £25m for Fulham teenager Ryan Sessegnon, with José Mourinho prepared to allow Luke Shaw to leave Old Trafford in order to sign the England youth international.

Sessegnon, 17, who finished as joint-top scorer at the European Under-19 Championship in June with three goals, has been tracked by United’s scouts for some time and has also attracted interest from Tottenham and Real Madrid. The European champions have watched the defender on several occasions this season and are understood to be monitoring his situation, while Spurs had a bid potentially worth more than £20m with add-ons rejected in the summer.

Despite usually operating as a left-back, Sessegnon is also capable of operating further up the field and has gained a reputation as one of English football’s brightest attacking talents. He became the became the first 17-year-old to score a hat-trick in the top four divisions of English football since Dele Alli when he inspired Fulham’s 5-4 victory over Sheffield United in November.

Fulham have indicated that it would take a bid in excess of £30m to tempt them into selling their prized asset, with manager Slavisa Jokanovic admitting on Thursday that he is unsure whether Sessegnon will remain at Craven Cottage.

“In this moment, I am not thinking of being without him for the season, but it is not under my control,” he said.

“All the questions are what the value of this player is, but myself, as a coach, I prefer to stay with the more important players for the competition that is ahead of us, but on the other side I can understand the business side too. If we want to be competitive we must keep our important players.”

Should United have a bid accepted, Tottenham are expected to renew their approach but have also enquired about Shaw, who has fallen out of favour at Old Trafford under Mourinho. The 22-year-old has played just 328 minutes in the Premier League so far this season having joined United from Southampton in 2014 for £30m, although any move for Sessegnon is not believed to be contingent on him leaving.

Tottenham are also interested in signing Sessegnon’s twin brother, Steven, who also plays for Fulham and starred for England’s Under-17s in their World Cup victory earlier this year. Along with Arsenal, Chelsea and Manchester City, Mauricio Pochettino also retains an interest in Crystal Palace’s Wilfried Zaha but Crystal Palace are adamant that the £50m-rated forward will not be sold in January.