He becomes United's third summer signing following full-back Aaron Wan-Bissaka and Daniel James
Harry Maguire is set to become the world's most expensive defender after Manchester United agreed to pay Leicester City £80 million ($97 million) according to media reports on Friday.
The 26-year-old central defender --coveted by United since he starred as England reached the World Cup semi-finals -- is to undergo a medical at United over the weekend, according to Sky Sports and the BBC.
Maguire's fee out-strips Dutch international Matthijs van Ligt who in July moved to Juventus from Ajax for a combined fee of 75 million euros ($84.2 million) plus 10.5 million euros of add-ons.
De Ligt's compatriot Virgil van Dijk cost Liverpool £75 million when he moved from Southampton in January 2018.
Maguire becomes United's third summer signing following full-back Aaron Wan-Bissaka and Daniel James, who arrived from Crystal Palace and Swansea respectively.
Maguire made 69 Premier League appearances for Leicester after joining from Hull City in 2017 and signed a new five-year contract with the Foxes last September.
United's transfer business is unlikely to stop there with a potential swap deal involving Argentinian striker Paulo Dybala joining them from Juventus and Belgian international Romelu Lukaku moving to the Italian champions.