There are few driving offences more likely to provoke the easily incensed than hogging the middle lane.
For some, monopolising that grey strip of tarmac in the centre of the carriageway is the motorist's carnal sin - up there with tailgating, stickers that read "princess on board" and aftermarket exhausts that make late '90s Fiestas sound like a flatulent hippopotamus.
And, according to new study, a section of the M25 near Sevenoaks is among the worst in Britain for middle lane hogs, with drivers spending more than 20% of their time in the centre lane.
The study looked at how often time spent in the middle lane exceeded that spent in the inside lane and found this happened 22% of the time on that stretch of the M25 in Kent.
A related survey found the worst offenders are older drivers, aged over 65, despite the fact they are most aware it is illegal.
As many as 59% of over-65s surveyed knew lane hogging is an offence, punishable with a £100 on-the-spot fine - yet 66% admitted to it compared to the national average of 59%.
Only 41% of those aged 18 to 24 even realise it is against the law.
One in 10 motorists admitted to always or regularly driving in the middle lane. Whether they did so while towing a caravan was not recorded.
Unsurprisingly the M25 was the worst road overall for the offence with five sections in the top 10. But the worst in the country is the M4, near Slough, which boasts the highest levels of lane hogging, with drivers spending 27% of their time cruising down the centre.
The Direct Line study analysed traffic flow data from nearly 6,500 sites on the Highways Agency motorway network, and surveyed 2,034 UK adults in June 2014.
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