The two clubs are said to be discussing a fee for the 18-year-old, who is highly rated at Tottenham Hotspur's academy despite having yet to make a senior competitive appearance for the club.
Thompson signed his first professional contract with Spurs last year and has trained regularly with the first team, having also earned a place on the bench for their Champions League fixture against Borussia Dortmund.
The England Under-18 international helped Tottenham's Under-17 side win the 2025 U17 Premier League Cup, and has continued to catch the eye at youth level since, including a hat-trick in a Youth League fixture against Slavia Prague last season. He has also won multiple caps for England at Under-18 level.
Manchester United have already been busy strengthening their squad this summer, having brought in Youri Tielemans and Andrey Santos to reinforce Michael Carrick's midfield options. Thompson would represent a different kind of addition, with United's recruitment staff keen to add promising young attacking talent to their academy ranks, following the template of Ayden Heaven's development since his move from Arsenal in 2025.
Any deal for Thompson would be a formal transfer, given he only turned professional at Tottenham last year, and the north London club are understood to rate him highly as one of their brightest academy prospects.
United are understood to have only become aware of Thompson's potential availability in the past couple of weeks, but have moved quickly to try to get an agreement in place, with a medical reportedly being planned before any transfer could be finalised. There is believed to be competition from elsewhere in Europe for his signature, with the winger's development pathway seen as a key factor in any decision over his next club.
Standing over 6ft tall, Thompson primarily operates on the left flank and is regarded within Tottenham's academy as one of the standout talents to have come through the club's youth system in recent years, having joined from Lambeth Tigers at Under-12 level.