This is not BMP's style at all. When it launched in 1968, the limit of its ostentation was to insist that the company's name - Boase Massimi Pollitt - featured in red letters on its fleet of chocolate-brown Minis. The agency ignored its 10th birthday, held a staff meeting to mark its 20th, and celebrated its quarter-century with a drink (just the one, apparently) and a slice of cake in the office.
The idea of a party was, frankly, alien, much less a celebration that involved packing out the Albert Hall with 5,000 guests and a cake the size of a garden shed. The other significant moment in the whirl of Happy Birthdays was the announcement that Chris Powell, the agency's public face since anyone can remember, was stepping down as chief executive and taking on the more hands-off role of chairman to accommodate his extra- curricular activities.
Mr Powell, among other things, is deputy chairman of the Riverside Community Health Trust, sits on the board of United News and of a local arts council in west London, and is a member of the marketing forum appointed by the New Millennium Experience Company to act as a litmus group on selling the Dome.
"I've been working on projects outside the agency for four or five years now," he says, "and it was getting embarrassing to have the title of chief executive when other people were running the agency. "
Powell, 55, joined BMP in 1969. He was appointed to the board in 1972 and made managing director three years later. He is one of the most respected practitioners of his trade.
"Advertising is all I have ever done and it's a bit dull to do only one thing in your life," he explains, insisting that his public sector endeavours are not rooted in altruism, or an attempt to correct the perception of the advertising industry as a conscience-free zone. "Working on a health trust is about as different an agenda as you can get from advertising. It's interesting to work with people, district nurses in the main, much more motivated by the satisfaction of their job.
"But, in the end, I fear I have a butterfly mind. The joy of advertising is that you get to look at so many different problems and put your nose into other people's business. It's a fantastic privilege to be able to do that and give your useless opinions to different people. Although I really can't claim I'm running around doing good works. It's selfish. I'm politically interested and involved. It's the satisfaction of Powell's interests and hobbies."
Powell is a political animal. It runs in the family. His elder brother Charles was Margaret Thatcher's foreign affairs adviser; his younger brother Jonathan is Tony Blair's chief of staff. Powell has been a Labour Party member all his adult life and once ran for the Greater London Council before masterminding BMP's landmark anti-GLC abolition advertising campaign in 1984. The "Say no to no say" campaign was never going to prevent abolition, but it alerted Labour to the possibilities of advertising.
"The left had regarded advertising as a tool of right-wing capitalism and something that was there to hurt it rather then help it," says Powell. "I think the right-wing left, such as Roy Hattersley, had a distaste of advertising, rather an aesthetic distaste, based on a dislike of bra advertising on escalators."
Powell agrees that it was largely on the basis of the GLC work that he and BMP were approached by Peter Mandelson to form the nucleus of the Shadow Communications Agency, first at the 1987 general election, then again five years later.
On both occasions, the winning campaigns belonged to the losing side, a fact which Powell finds reassuring. "It would be a terrible comment on humanity if such things made a huge difference," he says. "That said, it probably did help see off the SDP. The predictions made with good reason in the mid-Eighties were that Labour would become the third party. No sane person thought Labour would win in 1987, but the campaign ensured it remained the main party of opposition. It gave Labour the feeling of front-footed professionalism."
If Mandelson was the father of New Labour, then Powell was its kindly uncle. So, does someone who has been so intimate with Labour's communications effort have a view on how the recent fuss has undermined the party's ability to stay on message? "Yes, but not in The Independent," he says.
Powell is rather more forthcoming about BMP and its 30 years of success. Campaign produced a commemorative issue that recalls just how many BMP campaigns, characters and slogans permeated popular culture and passed into the vernacular of their time - "Watch out, watch out, there's a Humphrey about" (Unigate); "It's frothy man" (Cresta); "For mash get smash" (Smash); "Tell 'em about the honey mummy" (Sugar Puffs); and "Follow the bear" (Hofmeister).
Awards and praise have been piled on work for Courage, John Smith's, Volkswagen and the Health Education Authority's Aids-awareness campaigns. Like their spokesman for three decades, BMP's work is thoughtful, often understated but highly effective.
Stefano Hatfield, editor of Campaign, says: "BMP has always created campaigns that are liked by both the industry and the public. They have an excellent populist touch. Chris sets the tone for the agency's decency. He's not luvvie, so he doesn't raise the hackles. He's self-effacing, but he is evangelical about the power of advertising."
Powell also seems to have a healthy sense of there being more important things in life than advertising. Such as cricket, for example. Legend has it that in the Seventies BMP hired on the basis of cricketing ability. An ad for the creative department once read: "Wicket-keeper wanted. Copywriting skills an asset."