In a survey of 2,000 drivers more than a third admit they allow their assumptions to affect them behind the wheel, meaning they are intentionally more or less reckless as a result.

The research for Continental Tyres also revealed that we are twice as likely to not let someone out at a junction if they are in a flash car because ‘they think they’re it’. Yet, the biggest reason why drivers will not let someone pull out is if they can see the other person at the wheel using their mobile phone.

It was also revealed was that six in ten get agitated by a sticker for a rival sports team or in support of a cause or organisation.

Mark Griffiths, spokesman for Continental Tyres, said: “It is alarming that millions of drivers will change their driving style based on a prejudice about something as unimportant as how clean a vehicle is.

“Keen observation is vital for road safety and this study was part of our commitment to making driving safer, while trying to understand the ways that motorists behave.“

The top 10 of drivers we are least likely to let in at a junction are:

• Anyone using a mobile phone
• Performance car
• Towing a caravan
• Flash car
• 4×4
• Taxi driver
• Learner
• Bus
• Van
• Pensioner