You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Scottish_Parliament

Context:
For the Conservatives, the main disappointment was the loss of Edinburgh Pentlands, the seat of former party leader David McLetchie, to the SNP. McLetchie was elected on the Lothian regional list and the Conservatives suffered a net loss of five seats, with leader Annabel Goldie claiming that their support had held firm. Nevertheless, she too announced she would step down as leader of the party. Cameron congratulated the SNP on their victory but vowed to campaign for the Union in the independence referendum.

Question:
Who congratulated the SNP while vowing to campaign against their referendum?

Cameron