On 2 December 2005, the Go-Ahead Group purchased Diamond Bus[1][2] and in February 2006 Probus Management[3] (trading as People's Express) with over 100 vehicles and merged the two companies to form Go West Midlands.

[4][5] In 2006, Diamond relaunched its image, by increasing its frequency on route 16, which basically matched that of Travel West Midlands and increased its frequencies on routes 17, 63, 64, 74 and 87.

Diamond also lost many Centro and Staffordshire County Council contracts to other operators.

In March 2008, Go West Midlands was sold to Rotala and rebranded as Diamond Bus.

[6][7][8] As at March 2007, Go West Midlands operated a fleet of over 130 buses.