The start button on my 2009 Bentley GT does not always start the car. I have my my foot firmly planted on the brake pedal and the start button is then fully depressed and nothing happens - it’s as if the battery is dead. Inserting and turning the key, the car starts right up. This phenomenon occurs about 1 in every 20 startups. It has occurred at random, with the first start up in the morning as well as re-starts during the day so I doubt it is the battery.