Car manufacturer warns that decisions will not be made "in the dark" as Theresa May indicates that Article 50 could be triggered by the end of March.

Delivered days after Renault-Nissan chief executive Carlos Ghosn demanded reassurances about the possible effects of future trade tariffs for UK-based firms, the Prime Ministers’ speech delivered during yesterday’s Conservative Party Conference set-out a timescale for the EU split.

Liberal Democrats leader, Tim Farron, suggested that Mrs May’s comments suggested a move out of the EU’s single market and said that the move would “spell disaster for British jobs, businesses and the UK economy”.

Last Thursday Renault-Nissan Alliance boss Ghosn told media at the Paris Motor Show that investment in Nissan’s Sunderland plant would be halted until the government made “commitments for compensation” in the event that trade tariffs were imposed upon Britain in future.

Plant Sunderland produces around half a million cars each year, many of which are destined for overseas markets, and the facility employs nearly 7,000 people.

Ghosn said that Nissan had no plans to close the plant but said that “important investment decisions would not be made in the dark”.

President of the European Council, Donald Tusk, was quoted in the FT as praising Mrs May’s speech for its provision of “clarity” on the Brexit issue, however.

Jaguar Land Rover chief executive, Ralph Speth, told the Guardian as stating that Jaguar and Land Rover brands were already feeling the pinch of European customers who are boycotting the brands in light of Britain’s vote to leave the EU.

The newspaper reported that JLR believes it will miss out on £1bn in profit over the coming decade if UK goods incur tariffs at the World Trade Organisation rate of 10%.