Pascoe-Watson said that although the political knowledge was welcomed, Wallace’s skills as a campaigner were a deciding factor.
He commented: ‘Of course it is good to have people with Conservative links and knowledge, but Mark’s greatest strength is that he is an ultimate communicator.’
Wallace is known for his PR stunt such as dumping dead fish on the European Parliament's doorstep to protest against the Common Fisheries Policy
He will be able to utilise his campaigning skills ‘where appropriate’ according to Pascoe-Watson and will continue to write a weekly column for conservativehome.com as well as his own blog, Crash, Bang, Wallace.
‘We have told him that as this is a communications company he is welcome to continue his writing,’ Pascoe-Watson added.
Meanwhile, Portland has also hired Idil Oyman, head of Cameron’s regional media during the election, as an associate director to help lead the firm’s International Affairs practice.
Before moving to London in 2007, Ms Oyman spent 11 years in Washington, DC working in communications and politics.
Portland has also appointed Sophie Middlemiss as senior account manager in Portland International Affairs. She joins from the Foreign and Commonwealth Office where she was David Milliband’s speechwriter.