Proximity won the business after a pitch against EHS Brann, Tequila\ and Tullo Marshall Warren, in a pitch handled by COI.
Proximity will now be responsible for creating direct marketing campaigns across the entire IPS business, which will include work on ID cards, passports and the General Register Office.
The agency will work closely with its sister agency, Abbott Mead Vickers BBDO, on the campaigns. AMV won the above-the-line account in March.
The introduction of national ID cards has been a contentious issue in recent weeks, with the scheme – which would see UK residents over the age of 16 years old carry a card containing all their biometric data and identity details – being fiercely opposed by the Conservative Party.
The pressure forced the home secretary, Alan Johnson, to confirm this month that the scheme would now be voluntary rather than compulsory.