The uniqueness of credit unions is that they put together the principles and benefits of financial cooperatives, consumer cooperatives and mutual aid funds, born once by trade unions. Typically new members of the credit union become citizens having suretyship or recommendations from their friends - members of the credit union. In the UK, credit unions are a source of financing of people groups. This tool is not widely used. A potential new member of a credit union must submit a recommendation of shareholders in which the referee becomes a warrant of a future member of the credit union.