On the one hand, one should not swear at London taxi drivers, who in my not inconsiderable experience are a fine and upstanding body of men.

On the other, London taxi drivers should not abuse or hound the Mayor of London, which was evidently the case here.  The video passed to the Sun (£)l catches only the end of the exchange.

And that is more or less the end of it – though this site has no option but to impose our iron rule of blanking out the vowels in the offenders’ names for a month.