Ryanair cuts flights to London from City of Derry Airport
Ryanair is reducing services between City of Derry Airport and London
The airline said it will cut the weekly service to London from seven down to six from October 30.
The low-cost airline, that campaigned aggressively for Britain to stay in Europe, has said it will focus more on growing at airports in the EU and less on the UK.
It warned last month there could be further implications if the UK is unable to negotiate access to the single market and the open skies regulatory framework currently in place across the EU.
SDLP Foyle MLA Mark H Durkan has expressed his concern at the move.
Mr Durkan said: "This announcement is a bleak omen for what is to come if the North is dragged out of Europe against our will.
"Before the 23rd June, industry leaders and experts, including Ryanair CEO Michael O’Leary, warned that Brexit would damage economic growth and act as a barrier for businesses operating in the North.
"Ryanair’s move to scale back services in the North, only months after announcing new routes from Belfast, is evidence that the toxic fallout from the EU referendum is already having a decidedly negative impact on our economic future.
"Our people recognised that our economy is better served by remaining a full member of the European Union. We have not given our consent to a change in our constitutional status that has already proven itself to be harmful to business growth. We will continue to fight to ensure the will of our people is respected."
The low cost carrier made a return to Northern Ireland earlier this year, and now flies 11 routes from Belfast, with five daily flights to London's Gatwick.