Mutual insurer UIA has strengthened its grasp on the seven million-strong trade union affinity market by acquiring a £2m stake in intermediary Uniservice.

The deal gives UIA a 49% stake in Uniservice, an intermediary formerly wholly owned by the banking and finance union Unifi, which has 500,000 customers in 14 trade unions.

It will also enable UIA to sell its general insurance products to members of Unifi and the Manufacturing Science and Finance Union.

More than 20,000 household policyholders currently with Uniservice are to transfer to UIA.

Commenting on the joint venture, managing director of UIA, Eddie Dove, said: “UIA, as a mutual insurer, will be able to expand its policy base, thereby reducing premiums for all its members.”

He added: “UIA and Uniservice also see this as a springboard to the development of further opportunities with other trade unions.”

Chief executive of Uniservice, Bob Drake, said: “UIA has vast experience of providing household insurance that has been designed and developed specifically for members of a number of trade unions, including Unison, the largest trade union in the UK.”

Both companies are to retain their trading names.