Ounsley joins WWF later this month as head of public affairs, reporting to director of comms Winnie De-Ath. She fills the role vacated by David Norman, who has left to be director of comms and policy for the Liberal Democrats.
She has, for the past six years, been special adviser to the Government's chief whip in the House of Lords.
Ounsley will lead a five-strong public affairs team and oversee the political strategy around its ‘One Planet Living' campaign, which aims to reduce the UK's ecological footprint (the impact that the country has on the environment).
WWF UK director of campaigns Paul King said: ‘Political parties seem to have woken up to the fact that there are electoral opportunities from environmental issues and we must now convert that will into political action.'