Tottenham will demand at least £35million from Manchester United for Croatia midfielder Luka Modric.
United are set to beat Chelsea to the Spurs playmaker, once the he returns from Euro 2012, but had hoped to pay around £25m initially with a further £5m in performance-related additions.
Modric is in line for a bumper four-year contract worth £125,000-a-week, and £26m in all.
The 26-year-old midfielder is preparing for Euro 2012 with the Croatia squad but will sort his future once his tournament is over.
Slaven Bilic’s side face a fight to qualify from a tough group, which contains Italy, Spain and the Republic of Ireland, their first opponents of the tournament in Poznan on Sunday.
Despite the £17m signing this week of midfielder Shinji Kagawa, United fans have been desperate for the club to splash out on a big name.
Supporters are concerned that United’s spending power in the transfer market in being inhibited by using funds to pay off the owning Glazer family’s debt.
Tottenham had to fight to keep Modric out of Chelsea’s clutches last year.
But with Harry Redknapp’s side narrowly missing out on Champions League football next season, the club look likely to lose several big stars this summer.