The Porsche Carrera Cup GB commenced in 2003 and Westbrook was immediately a front-runner. Between 2003 and 2005, he was dominant; taking the title in 2004 (seven wins, 17 podiums, eight pole positions, four fastest laps) with Redline Racing and finishing as runner-up in 2003 (Team BCR), and 2005 (Redline Racing). Indeed, his 2005 totals for victories and pole positions (14 wins, eight pole-positions) are both series records and he went on to take 16 podiums across the season. Having done a few Supercup races in 2002 with Kadach Racing Team and in 2003 with Porsche Cars Great Britain, Westbrook returned in 2005 in a Lechner Racing School Team prepared Porsche in rounds which did not clash with his UK commitments. He won the season opener in
Bahrain and came ninth overall, adding a fastest lap to his tally too. In 2006 with RT Morellato PZ Essen (four wins, 11 podiums, four pole positions, three fastest laps), Westbrook finished every Supercup race on the podium, wrapping up the title with two races to go, against drivers such as
Uwe Alzen,
Alessandro Zampedri and
Patrick Huisman. He has also competed in several Carrera races in Germany (EMC Buchbinder ARAXA Racing – one win, four podiums, two fastest laps) and also back in the UK (Red Line Racing – four races, three wins, two fastest laps) where he alternated with
Danny Watts. In 2007 with HISAQ Competition, Westbrook won his second Porsche Supercup title in a row, with wins in Spain and Hungary, along with five other podium finishes and fastest laps. He again competed in Carrera Cup Deutschland, finishing second in the championship for ARAXA Racing (five wins, one pole position, four fastest laps). In the same year, he made his debut in the Le Mans Series in a GT2 Porsche for James Watt Automotive and in the
Rolex Sports Car Series at Daytona and Watkins Glen with Synergy Racing in a Porsche GT3 Cup Car. 2008 – see next chapter 'Porsche Factory Driver'. In 2009, Westbrook drove for
VICI Racing (T-Mobile VICI Racing) in the American Le Mans Series (including the Sebring 12h) and for Prospeed Competition in the FIA GT Championship. In his first ALMS race of the year, he finished fourth at Long Beach, alongside Johannes Stuck. However, it was in the
FIA GT Championship where he would achieve his biggest success, winning the GT2 class overall after victories at Silverstone (UK), Adria (Italy), Hungaroring (Hungary) and Zolder (Belgium) backed up by second places in Algarve (Portugal) and Paul Ricard (France), in a Porsche 911 GT3 RSR (997). In the same year he also made appearances in International GT Open,
ADAC GT Masters,
Rolex Sports Car Series (including the Daytona 24h – 15th), Porsche Carrera Cup Deutschland,
Porsche Supercup, and Belgian GT. In 2010, Westbrook made his debut in the
24 Hours of Le Mans in the GT2 class, driving a Porsche 997 GT3-RSR for
BMS Scuderia Italia alongside
Marco Holzer and
Timo Scheider; the trio finished 14th overall and third in class (GT2). He also competed in three further 'twice round the clock' events, the 24 Hours of Spa (Prospeed Competition), the 24 Hours of Nurburgring (Haribo Team Manthey), and the 24 Hours of Daytona where he finished third overall in the Crown Royal/NPN Racing BMW Riley alongside
Ryan Hunter Reay,
Lucas Luhr, and
Scott Tucker. There were also outings for Westbrook in the Le Mans Series for Prospeed Competition, but it was his stand-out star performances in a Matech Ford GT1 during the final six rounds of the 2010
FIA GT1 World Championship that would turn heads, taking three podiums alongside Thomas Mutsch. Westbrook also took part in the
British GT Championship in 2010 (three podiums, one pole position, one fastest lap), helping Trackspeed team owner/racer David Ashburn to the title that year.
Porsche Factory Driver (2008–2009) After multiple successes in Porsches, Westbrook signed with the German marque to become the first British Porsche factory driver since Derek Bell in the 1980s. He competed in a global programme that included the
FIA GT Championship (Prospeed Competition),
Le Mans Series (Farnbacher Racing) and
American Le Mans Series (Farnbacher Loles Motorsport). He was the only driver to win at least one race in all three categories. He also competed in three 24-hour races; Spa 24h (Prospeed Competition – GT2 – sixth), Daytona 24h (TRG – GT – second) and the Dubai 24 Hours (Proton Competition – A6) == Corvette Factory Driver (2011–2015) ==