His soft-toned insistence jars with the rabble clearly audible in the background as Stephen Dorrell, the Secretary of State for Health, slugs it out "live" on television with his opposite number, Harriet Harman, in the House of Commons.
As the country's MPs discuss the public health disaster with their usual decorum, Mr Parker argues that Big Mac, McDonald's "flagship", bestselling product (1.8 million are sold a day), will survive this crisis as it has the previous British beef scandals. Public confidence will return later this week when British beef is replaced by meat imported from Europe. Then the cheese burgers and Big Mac meals will be back on the menu; it will be business as usual at the 665 restaurants owned by McDonald's, the ever-expanding burger industry's market leader.
If only life - and customers - were that simple. In the McDonald's off the Holloway Road, north London, Trina, 27, is sharing an egg-and-bacon muffin with her daughter Danielle, aged four. A visit to McDonald's is a twice-weekly treat. But it has been three months since mother and daughter have had burgers.
"During the last scare before Christmas I just emptied the fridge and freezer," says Trina, who also has a son Mark, aged six. "Out went sausages, hamburgers and meat pies. I haven't bought any beef since. I won't even buy beef stock cubes or crisps. My husband loves steak but he knows I won't have beef in the house. It is hard because we were such meat-lovers and the kids loved burgers."
Trina wrote to Mark's school at Christmas insisting he was not fed beef in any form. Shortly after, it was removed from the school menu. She does not consider her total abstinence excessive. Her three brothers and sisters have also imposed a complete beef ban on their children. McDonald's switch to foreign beef will not bring her back to burgers. The BSE scare has made her aware of the lengthy journey from the field to the family table and a television documentary on Monday night which "showed a poor mad cow and a man dying with same symptoms" has only reinforced her doubts about modern hi-tech food production.
At a nearby table sits Daniella Buck, four years old like her near namesake but rather less compliant. Miss Buck is sweet and blond but her mother, Michelle, 23, says you do not mess with her when it comes to burgers. Daniella had her first burger when she was nine months old and now will not pass a McDonalds. She is a connoisseur; shunning Burger King because there the beef comes with salad. With burgers temporarily off McDonald's menu, she has been fooled with a flat pork sausage.
"There's murder if she doesn't get her burgers," says Mrs Buck. "Her brother Michael is two and will take chicken, but she won't give in." Mrs Buck is worried by the current crisis, but fatalistic. She thinks any damage is probably already done. "The doubts about Mad Cow disease have been there for years and we come here twice or three times a week."
There are 30 customers in McDonald's but all points of view are represented. Alex and Marios Aresti cannot wait for beef to be back on McDonald's menu and even argue that British beef should be a menu special.
The brothers eat meat every day and beef at least three times a week. "We just could not live without beef," says Alex, 21, a painter and decorator. "I deliberately changed channels when the BSE documentary came on." Drawing heavily on a Silk Cut he adds there is a risk to everything. Mario's approach is even simpler. "If you don't die one way, you die another."
Not every customer is that philosophical. David Shute, an advertising director, says the BSE scare threatens the "straight-line" growth enjoyed by McDonalds - which has a 72 per cent share of the market - and its closest competitor, Burger King. Despite the rise of the veggieburger and chicken burger, beef is still king and accounts for half of the 121,500 tonnes of burgers sold in Britain last year.
Behind McDonald's calm public face Mr shute says the advertising and marketing men are already hard at work. Mr Parker says McDonalds is planning only full-page newspaper adverts to publicise the switch to foreign beef. But Mr Shute believes a TV or radio campaign is probably already in production .
Few, if any companies, have faced such a monumental public relations crisis, he believes. But if anyone can pull it off, it will be McDonald's. "I predicted they would go for imported beef last Friday. It is the only way to deal with this. Burger King, Wimpy's and Wendy's have now followed. McDonald's is a highly professional outfit and it has always believed in the power of advertising. This crisis actually presents it with an opportunity to attract business from its main competitors and lots of small independent burger stores. Its message will be that McDonald's is the safest place to eat a burger."Reuse content