Brunel's Britain in Europe thinktank has called on the government to reassure EU citizens that they can continue to plan a future in a post-Brexit UK.
In a letter published in The Guardian the group urges leaders to "take positive action to demonstrate that they are an integral part of British society and their contributions are highly valued".
The warning comes as both incoming Prime Minister Theresa May and foreign secretary Philip Hammond failed to promise EU nationals that they can stay in the UK until negotiations had taken place.
"The argument put forward by May and Hammond is that Britain’s negotiating position will be weakened if assurances are now offered to EU citizens," the letter reads.
"Quite apart from the fact that it is unacceptable to use EU citizens living in the UK as bargaining chips, this argument runs the serious risk of making it more likely that other EU countries may be prompted to adopt a similar approach to UK citizens residing there."
The Britain in Europe thinktank was established to focus on human rights and criminal justice in the European Union. The group, the brainchild of Dr Dimitrios Giannoulopoulos of Brunel Law School, brings together academic scholars, legal practitioners and non-governmental organisations to influence public policy.
The full letter is published here.