Does London traffic slow-down account for capital's bike boom?

While you can argue about whether there's a general UK bike boom happening, there's no doubt London is having one. There are now twice as many journeys by bike in the capital as a decade ago. But the latest figures suggest the reason is simple: London traffic is now so slow a bike is far and away the fastest way to travel.

The Department for Transport's most recent figures for average traffic speeds on local A roads show that London has the ten slowest local authority areas in England during the morning peak — and it's getting slower.

The prizes for England's slowest traffic go to Camden and the City of London, where the average speed is just 9.2mph. Camden held the title for the 12 months to September 2013 too, but a six percent slowdown in the City, versus just two percent in Camden, brought them level.

The pattern is repeated all over London. Traffic is slower in inner London as a whole, with a fall in average speed of 6.1 percent between 2013 and 2014 to just 12.3mph. That's the lowest since 2006-7.

And speeds have also dropped by 7.4 percent on all the roads managed by Transport for London, despite Mayor Boris Johnson's policy of smoothing traffic flow. The 13.4mph average on those roads is also the lowest since 2006-7.

That makes a bike the fastest way to get around London's streets.

And it's not just London. Traffic speed blackspots elsewhere in the county include Bristol, with an average of 14.5mph,  Reading at just 13.6mph and Manchester at 15.4mph. That might be a bit more than a leisurely pootle to the office but it still makes cycling an attractive proposition when you consider the savings in fuel and parking charges.

The Department's average speeds are for traffic in both directions. In some London boroughs they may well reflect the average speed of the commuter run, but in larger areas  where drivers are mostly heading into town during the peak, the average likely masks a lower speed for the poor souls sitting in traffic.

Here are the figures for the 10 slowest areas inside and outside the capital.