Simplify the following text for a Grade 7 native English-speaking person.
Original: However on 9 December an agreement was reached with Formula One rights holder Bernie Ecclestone ensuring that the track would host the British Grand Prix until 2009 after which Donington Park would become the new host of the British Grand Prix .
Simplified: In December an agreement was reached with Formula One Silverstone would host the British Grand Prix until 2009 . Starting in 2010 Donington Park would become the new host of the British Grand Prix .