In an interview with ITV News, David Cameron would not take up the challenge to repeat the words "I won't cut tax credits and child benefit".
The challenge was put to Mr Cameron after Labour said "everyone knows the Tories are planning to cut tax credits and child benefit".
Speaking to ITV News presenter Ian Axton, the Prime Minister wouldn't use those exact words. He said he wants to "keep" child benefit, not cut it, saying it's "absolutely vital" and a "really important part of families finances".
On tax credits he said he would freeze it for 2 years.