Manganese Bronze, the company that makes London's famous black cabs, has posted higher losses for the half-year after its new mobile hailing system was delayed.

The 'Zingo' hailing system will allow people to contact the nearest free taxi through their mobile phone.

But the company said it was "disappointed" that progress on the system had been "slower than planned."

It said Zingo was now expected to be launched in the next financial year, and its cost was still estimated to be �8m.

The delays and costs of Zingo increased losses at Manganese Bronze to �1.99m for the six months to 31 January, compared to a loss of �1.81m for the same period a year ago.

On a brighter note the company said the license it signed to produce taxis in China was already "revenue producing."

Manganese Bronze struck a licensing deal with the Chinese car manufacturer Brilliance China Automotive Holdings (BCA) which aims to sell black cabs in China, Hong Kong, Macao and Taiwan.