Boris Johnson travelled to Northern Ireland today to officially open a production line for the new routemaster-style buses, the 'Boris Bus.'
Simon Harris reports.
Boris Johnson has now moved on to the main Wrightbus factory in Galgormm, where the complete buses are produced.
The new routemaster-style buses will cost £354,500 each.
But Transport for London claims that the final contract, signed with manufacturer Wrightbus, has saved millions of pounds for the taxpayer.
They say the contract "includes a competitive, fixed price deal for the vehicles - removing the risk and uncertainty of higher production and material costs, and inflation over the next four years".
TfL says the price is "broadly comparable with a standard hybrid double deck bus", with the difference "accounted for by the much higher specification of the new bus compared to a standard hybrid bus".
They also claim that the new bus is "the greenest diesel electric hybrid bus in the world".
The Labour Party has criticised the cost of the new buses, accusing Boris Johnson of being "lavish" with taxpayers' money. They will cost £354,500 each.
Val Shawcross, the Labour transport spokesman on the London Assembly, said:
"There are plenty of green, environmentally clean, buses available on the mass-market now...the mistake that Boris has made here, is he's gone for a new tailored bus so he's paying way over the odds.
"He's probably paying over £100,000 more for each of these buses, so it's a very large waste of money.
"We could be getting the environmental benefit without paying this huge premium."
Boris Johnson has travelled to Northern Ireland today to officially open a factory for the new routemaster-style buses.
The production line in Antrim produces the chassis for the buses.