The company said Ai's technology would enhance its clients' direct marketing and help them "target the most attractive prospects and build relationships with the most profitable and lowest credit risk customers".

Surrey-based Ai's services include customer list creation, data combination and cleansing, analysis of campaign effectiveness and credit checking.

Communisis chief executive Steve Vaughan said that the acquisition was a response to rising demand for such services among its client base.

He added: "Ai fits nicely into our portfolio and means we can offer a joined up solution and a range of services.

"We also share lots of customers, and expect to begin cross-selling between our client bases once integration is complete."

For the last two years, Communisis has followed a strategy to develop and increase its range of value-added services for customer communication.

It said the purchase of Ai is "a logical step in this investment stream", and brings data services in-house.

Clients of £6.7m-turnover Ai include RBS, BT and Lloyds TSB. Its founders and senior management will remain with the company.

Vaughan said: "These services will be a great fit with our recent investments in sophisticated campaign and delivery, and will complement our scale in direct marketing."

Last week, Communisis said it has set its sights on acquisitions following a deal to secure a £20m debt package from Lloyds TSB, announced on Friday.

Vaughan said he wanted a balance sheet to support acquisitions such as Ai and said that the company's strategy remained focused on businesses that can add value to its offering.