Steve Morgan, chairman of Morgan Allen Moore, spent the past week in New Hampshire as Clinton's international media co-ordinator. 'I've been speaking to members of the foreign press on issues that affect all of us, such as climate change,' he said.
The former Labour Party organiser performed a similar function for Al Gore and John Kerry's presidential bids.
Meanwhile, three UK union comms chiefs have been in the US as guests of the United Steelworkers union, observing the group's campaign work for candidate John Edwards.
Amicus communications director Richard O'Brien, Transport and General Workers' Union communications director Andrew Dodgson and Unite policy officer Clare Moody plan to return to the US after the nomination process.
O'Brien said: 'The idea is to take everything we've learned and translate it into campaigning for the Labour Party in the next election.'