Manchester United are set to make a third bid of about £55m for Chelsea midfielder Mason Mount.
The Old Trafford club will also warn they will walk away from negotiations with the Blues if the offer is not accepted.
Chelsea are thought to value the England international at £70m.
However, United feel that figure is excessive as Mount only has a year left on his contract and talks about an extension have stalled.
United have already had bids worth up to £40m and £50m for Mount rejected by Chelsea.
United boss Erik ten Hag wants Mount to become his first signing of the summer as he looks to strengthen his side following their qualification for next season’s Champions League.
Personal terms are not thought to be a problem and United are confident the player wants to make the move to Old Trafford.
Mount, who has scored 33 goals in 195 appearances for Chelsea since making his debut in 2019, missed the end of the domestic season with injury as the Blues came 12th – their lowest finish for more than 25 years.
He won the Champions League in 2021 with Chelsea and started their 1-0 win over Manchester City in the final. He also won the Fifa Club World Cup and Uefa Super Cup with the Blues.
The 24-year-old has been capped 36 times by England, scoring five goals, and was part of manager Gareth Southgate’s squad for the 2022 World Cup in Qatar.
Mount came through Chelsea’s academy before joining Dutch side Vitesse on loan for the 2017-18 season, scoring nine goals in 29 Eredivisie appearances.
The following campaign he was loaned to Derby County, scoring eight goals in 35 Championship games under manager Frank Lampard as the Rams suffered a 2-1 defeat by Aston Villa in the play-off final.
Upon his return to Chelsea in 2019, Mount made his breakthrough under the newly appointed Lampard and became a key player at Stamford Bridge.
Last month Chelsea appointed former Tottenham boss Mauricio Pochettino as their new manager, replacing interim boss Lampard who took over after Graham Potter was sacked.
Alex Howell, BBC Sport
The situation with Mason Mount has been bubbling for some time and now looks to be coming to an end.
Chelsea want to keep Mount but his contract situation, the lack of agreement and Manchester United’s long pursuit mean this is only going to end one way.
When Todd Boehly and the Clearlake group took over they made a point of not wanting to let players get into the last two years of their contracts. They had been stung the previous season when they lost Antonio Rudiger on a free to Real Madrid, which left them with a lot to do in the transfer market.
Chelsea made two contract offers to Mount last year and the wages would have been comparable to other big-name players at Stamford Bridge.
In an attempt to try and get a resolution to the situation, Chelsea even discussed with Mount’s camp the possibility of extending his contract for a year, increasing his money and giving everyone more time to find a solution – but like the other two offers, it was rejected.
The main issue with these negotiations is that the club and the player have not been able to agree on wages.
United look set to make another bid for Mount but that has not been formally sent yet and the Blues insist that if their valuation is not met, they will not sell.