These vehicles are exempt from the London congestion charge and are proving a popular buy for city-based fleets.
The milestone vehicle was bought by Woolwich-based building contractor Maulyte.
Savings of £1,696 are possible on the congestion charge alone, plus there are fuel savings too.
Typically, the cost of conversion (£2,000 ex-VAT) is saved in the first year of operation. The vans are powered by a 1.4i petrol engine offering 75bhp.