Aerospace, defence, security and space companies from the UK have rejected the proposal of a British exit from the EU, believing it would disrupt R&D funding and the supply chain.
In a survey from ADS Group, which represents these industries in Britain, 70 per cent of respondents said it would be better for their business if the country stayed in the EU.
European planemaker Airbus Group has also said its future investment in Britain could depend on whether the country remains in the EU, in a warning to its British employees ahead of the referendum on the issue on 23 June 2016.
"We all need to keep in the back of our minds that future investments depend very much on the economic environment in which the company operates," said the letter signed by Airbus's chief operating officer Tom Williams and its UK head Paul Kahn.
The company has already said it believes its British operations are more competitive because they are within the 28-member bloc.
Siemens and BMW have already warned that Brexit would be damaging to the future of the UK’s technology and manufacturing sectors and would hamper R&D on future technologies such as driverless cars.
Last month, the CBI claimed that leaving the European Union could cause a £100bn short-term shock to the economy due to the fractious trade talks that would be necessary with its 27 EU partners after a pro-Brexit vote.
"Our members recognise the benefits of the UK remaining part of the EU; access to integrated European supply chain; R&D funding which enables the UK to compete globally, and the ability to influence and shape EU regulation," ADS Chief Executive Paul Everitt said.
The industry's view echoed the comments of bosses at more than a third of Britain's biggest companies including major oil firms Shell and BP and its largest telecoms group BT, who warned in February that leaving the EU would put jobs and investments at risk.
Some companies, however, do favour a UK exit from the EU. The campaign for Britain to leave the EU has been backed by 250 business leaders, including the former chief executive of HSBC, the Vote Leave group said in March.
Members of the ADS group employ 310,000 people in Britain and generate £31bn in exports for the country. The survey was carried out in February and March, ADS said.
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