DfID director of comms James Helm (pictured) joins the agency in October as a partner in its international team in London, while former HM Treasury official Matt Pollard will join the team in August as part of Portland's Brexit Unit.
Helm had been with DfID since October 2010, prior to which he was deputy head of news and PR at the now defunct Central Office of Information. Before that he was a news journalist and worked for the agency Blue Rubicon.
The international team's global development clients include the Bill & Melinda Gates Foundation, the Qatar Foundation and the Mo Ibrahim Foundation. The unit has also worked with several agencies of the United Nations. Toby Orr, the senior partner managing the team, said there were "few people who know more about global development and global campaigns" than Helm.
The Brexit Unit, launched by Portland on Monday with a dedicated website, is a new proposition to help clients navigate what managing director Tim Allan calls the "risk and opportunity" of the UK's impending departure from the EU.
In addition to Pollard, the unit includes the agency's chief economic adviser Kitty Ussher, managing partner Steve Morris and several other members of its advisory council, including former UK ambassador to the EU Sir Stephen Wall, who joined the agency on a part-time basis last year, and former Polish minster Radek Sikorski, who joined in May.
Allan said: "Clients want to know how to engage the debate in the right way. And they want to know how to communicate with their own people and externally as they navigate their way through a period of uncertainty that will last for years."
Alex Aiken, executive director of government comms, said of Helm: "James has been a hugely influential and successful member of the leadership team that has improved government communication, and a critical part of our Britain in the World work. He's made DfID into one of the top teams in government communication, evinced by the Syria Summit, their digital communications and media work to explain the importance of international aid."