London Mayor Boris Johnson has indicated that buses made by a Ballymena firm currently on trial in London will get the thumbs up in a potentially multi-million pound deal.
Eight buses built in Co Antrim and modelled on the iconic Routemaster vehicle, which was 'retired' in 2005, are currently being driven around the streets of London after Wrightbus was awarded a contract in 2010 to design the first new commuter bus for the city in fifty years.
The bus is a hybrid vehicle that employs green technology, uses less fuel and features three entrances and a double staircase.
Now bike fan Boris Johnson - who visited the Wrightbus plant late last year and called the vehicles "revolutionary" and "world class" - has told North Antrim DUP MP Ian Paisley Jnr by letter that up to 600 of the buses could be ordered over the next four years.
He said: "I remain committed to the rollout of 600 production vehicles between now and 2016," adding that the deal marked "good news for manufacturing jobs in Northern Ireland and for travellers in London".
Mr Paisley said that such an order would last for years and will develop job security in Northern Ireland.
"At a time when we need economic growth and job security we now have a commitment that potentially 600 buses could be built in Northern Ireland," he said.
Last year Wrightbus won an order from Great Britain for 334 new buses.
The contract with bus operator Arriva is valued at around £55m and consists of 204 double-deck and 130 single-deck buses.
Wrightbus said it would not comment on the London Mayor's letter yesterday as negotiations are still ongoing between the firm and Transport for London, which operates the public transport network in the city.
North Antrim Ulster Unionist MLA, Robin Swann, added that the buses currently on trial are a fantastic advertisement for Wrightbus and local industry across the province.
"If Wrightbus were to be successful in receiving the order for the 600 buses needed by Transport for London it would be a massive boost for our economy."
"At a time of economic uncertainty such a massive order would secure a lot of jobs and the high profile nature of the London buses would be sure to generate more interest in what we have to offer in Northern Ireland," he added.