The organisation’s research found that three-quarters of Brits (73%) would rather go the extra mile to make the outside of their motor gleam than tackling the inside where the filth is allowed to flourish.

Among those that admitted to cleaning their cars in the last seven days, more opted to wash the outside (24%) rather than do away with the dirt inside (14%), with two-fifths (39%) saying they think it's “important to have a clean-looking car from the outside”.

And, when asked about their car cleaning habits over the last seven days, twice as many men (19%) than women (10%) admitted to giving their cars a good going-over inside and out.

However 9% of those surveyed said they hadn’t cleaned their cars in more than six months, which combined with the 2% who never clean theirs at all, means there are 3.3m TLC-neglected motors on Britain’s roads.

The RAC Cars research showed most motorists (48%) prefer to wash the outside of their cars themselves, followed by 29% who opted for a hand-washing expert. Just 7% say the automated car wash is their top choice for a regular rinse.

RAC Cars spokesman Pete Williams said: “The importance of cleaning the car clearly varies from household to household but our research has found much greater preference for washing the outside as opposed to vacuuming and dusting the inside. We suspect the reason for this is not wanting to be seen driving around in a filthy-looking car which means if there’s only limited time to give the car some TLC, the outside takes precedence.

“Unless you give friends or colleagues lifts, not many people get to see the inside of your car so you can get away with it not being that clean. And, interestingly, despite the prevalence of automatic car washes and independent car cleaning companies, the DIY clean was still preferred by many.

“But cleaning the car yourself can mean you are subjected to the most annoying phrase of all – ‘you can do mine as well if you like’. Perhaps we need to challenge the nation to come up with something a bit more original if they spot their neighbour with the hosepipe and bucket.”