The climate change campaign group threw green custard at business secretary Lord Mandelson earlier this morning, protesting at his involvement in approving Heathrow airport's third runway earlier this year.
'If you are attempting to persuade government, alienating them is probably the wrong place to start', said Westminster City Council director of comms Alex Aiken. 'When you start using tactics that involve physically attacking someone, I don’t think any PR professional can justify that', he said.
Bowel Cancer UK's director of press, PR and public affairs Ian Beaumont questioned the effectiveness of the action. 'If you are trying to get a serious point across, then I've very wary of anything that has the word stunt attached to it. All people remember is the stunt, not the cause. If you’ve got a strong enough cause, that speaks for itself', said.
Others highlighted the way that Mandelson had effectively dealt with the incident from a comms perspective.
Edward Staite, senior media adviser at Fleishman Hillard, said: 'Peter Mandelson handled this attack like a true media pro he is. Keeping calm, he ducked away from the waiting cameras before swiftly retreating inside to safety - ensuring no pictures were taken of his guacamole covered head. Minutes later he was broadcasting to the nation and firmly back on message: the original New Labour sultan of spin.'
Graham Macmillan, CEO of Open Road, said: 'This stuff happens to politicians from time to time. You have to be calm and not react, which is exactly what Mandelson has done. His reaction shows he is a seasoned PR professional.'
Plane Stupid campaigner Leo Murray defended the actions. 'Yes this is a silly prank, but it is a silly prank that has allowed us to articulate the reasons why we did it', he said.
'There are other ways to have your voice heard but they are being pursued by established organisations like the National Trust and they haven't worked. Emissions are still going up and we are careering headlong into the end of the world as we know it. So if today's stunt smacks of desperation, that's because we are desperate.'