Sir Philip Dilley has resigned from his post as chairman of the Environment Agency.
He faced heavy criticism during the recent flooding for holidaying in the Caribbean.
The wettest month on record in the UK saw parts of northern England, including Yorkshire and Cumbria deluged by heavy rains.
It left thousands of homes and businesses without power during Christmas and beyond.
Sir Philip said: “My reason for resigning is that the expectations of the role have expanded to require the Chairman to be available at short notice throughout the year, irrespective of routine arrangements for deputy and executive cover. In my view this is inappropriate in a part-time non-executive position and this is something I am unable to deliver.
“Furthermore the media scrutiny focused on me is diverting attention from the real issue of helping those whose homes and businesses have flooded as well as the important matter of delivering a long-term flood defence strategy. This same media attention has also affected and intruded on my immediate family, which I find unacceptable.”
He stepped into the role as part-time chairman in September 2014.
Environment Secretary Elizabeth Truss added the current Deputy Chairman Emma Howard Boyd has agreed to become Acting Chairman with immediate effect.
Last month the government announced extra funding worth £50 million to support households and businesses affected by the floods.