To publicise the low fuel costs of the Leaf electric car, Nissan is going to offer free cab rides this weekend.

To grab a ride, all a prospective passenger has to do is send a Tweet that incorporates the hashtag '#6XCHEAPER' and their chosen destination. Nissan is also using the activity to gather consumer feedback on a potential taxi of the future.

The '#6XCHEAPER' tag emphasises that fuelling an electric vehicle is six times cheaper than a similar sized petrol car. Using off-peak electricity, Nissan estimates it costs just 1.75 pence in fuel to travel one mile in a Nissan Leaf, but more than 10 pence per mile in a conventional car.

"By offering free taxi rides, we aim to show hundreds of people just how practical and affordable the Nissan Leaf is to run. As each journey costs us so little, we're not charging passengers - there's no point quibbling over a few pence." said Jim Wright, Managing Director of Nissan GB.

The fleet of Nissan Leaf EVs will be based at their very own 'taxi rank' at the Truman Brewery, near Liverpool St Station and will be giving free rides to destinations across London. That means as far west as Turnham Green or to the O2 Arena in the east. Nissan says the Leaf cabs will go south of the river as far as Clapham and as far north as Hampstead. They will be operating from 10am to 6pm on both Saturday and Sunday and driven by professional drivers from car service operator, Climate Cars.

All Tweets sent with the '#6XCHEAPER' hashtag will be monitored. Each journey will be logged and passengers shown just how much they would save in fuel costs by going electric.