The agency won the £5 million above-the-line account after a three-way pitch against Publicis and St Luke's.
National Savings has been without a creative agency of record since BMP DDB's contract expired 18 months ago. Since then, it has relied on its direct marketing incumbent, EHS Brann, for its brand advertising.
EHS Brann is currently pitching against TBWA/ GGT for the direct marketing business, although the result of this pitch is as yet unknown.
In addition, OMD UK has retained the media planning and buying business, while Ptarmigan Media will handle media for specialist, trade and financial press advertising.
In reference to the media review, the NS&I head of communications said: "The challenge is to make NS&I the first port of call for people with money to save and invest."
NS&I rebranded through Citigate Lloyd Northover in February this year.
The process cost around £2 million and was followed by a press and direct marketing campaign for premium bonds using the strapline: "National Savings & Investments can make you a millionaire."
With the rebranding work out of the way, it's currently unclear what role TV will play in the future marketing activity of the government savings organisation. NS&I has not advertised on TV since March 1999. For the past three years it has relied largely on print advertising and DM.
Another NS&I spokesman Mark Brooks denied a decision had been made on the creative review. WTCS refused to comment.