FILE PHOTO: British Union Jack flag and European Union flag are seen at the courtyard of the Prime Minister's Office in Luxembourg, September 16, 2019. REUTERS/Yves Herman/File Photo

LONDON (Reuters) - Britain needs to strike “proper, long-lasting” post-Brexit trade deals with both the European Union and the rest of the world, the boss of carmaker Rolls-Royce told Reuters on Tuesday.

Britain is due to leave the EU by the end of the month, guaranteeing a transition period until the end of 2020 during which time little will change in its relationship with the bloc.

Much of the rest of the year will be dominated by talks between London and Brussels on the future partnership to take effect from 2021, with manufacturers seeking the closest possible relationship to maintain their seamless production processes.

“What needs to be delivered are proper, long-lasting trade deals not only with the European Union but also with the entire rest of the world,” Torsten Mueller-Oetvoes said as the firm announced its sales rose by a quarter in 2019.

“Free flow of goods and people, that is very important for us.”