Bishop, who will oversee the allocation of one of the biggest ad budgets in the country, joins as the Cabinet Office is planning to give the government's Advisory Committee on Advertising (ACA) a bigger role in the running of Whitehall communications.
It will be allowed to pre-audit government departments who may be looking to run their own advertising rosters rather than use the COI.
While it will remain voluntary to use the COI, the Cabinet Office is keen to avoid a repetition of the fiasco earlier this year, when the then Department for Transport, Local Government and the Regions' broke away from the COI. It aroused controversy because of the DTLR's appointment of agencies already available to it through the COI (Marketing, May 2).
The breakaway is also understood to have been a major reason behind the departure of Bishop's predecessor, Carol Fisher, three months ago.
In future, the ACA will be able to register its objection to any such breakaway with Cabinet Office. The ACA includes senior marketers including Shell vice-president of global brands and communications Raoul Pinnell, Sainsbury's assistant managing director Sara Weller and Mike Moran, commercial director of Toyota GB.
"We are keen to see that the COI is strengthened and we believe that the Cabinet Office shares that view," one ACA member told Marketing.
The COI was the UK's biggest advertiser for the past financial year, and spent £160m on advertising.
Bishop, the former chairman of Saatchi & Saatchi International, beat off competition from candidates including Simon MacDowall, the communications director at the Department for Work and Pensions, and former Arthur Andersen marketing chief Eddie Bowman.
Bishop, who was unavailable for comment, is also expected to take on the additional role of chief adviser on marketing communications working alongside Alastair Campbell.