It's apposite that the direct descendant of Collett Dickenson Pearce sits off and to one side of the throbbing hub of media activity that is Soho's Golden Square.
Tucked quietly around the corner, cdptravissully has almost dropped off adland's radar. Hardly surprising since the agency, with a staff of just 25, occupies 70th spot in the current Campaign agency rankings.
Of course, it's been many years since CDP was at the top of its game with ads that proclaimed "Happiness is a cigar called Hamlet" or told drinkers "Heineken refreshes the parts other beers cannot reach". Or created the Hovis spot featuring a baker's boy pushing his bike uphill to Dvorak's New World Symphony.
Even when Japan's Dentsu paid an estimated $40 million for a 40 per cent stake of CDP in October 1990, the agency was long past its best. Today, CDP is an anachronism within a media landscape unrecognisable from when the agency was born. It was a product of the cultural shifts of the Swinging Sixties and a pioneer of the "if you don't like it, screw you" school of creativity.
Dentsu has been debating for some time whether to drop the CDP moniker (which it decided to do this week) but was said to be reluctant to rebrand it as Dentsu London until it was sure it would have an agency worthy of bearing its name.
"The CDP name was an advantage when everybody in the business knew what the agency was," a Dentsu source says. "But CDP was never an international brand and the world has moved on."
Indeed, there was no agency more quintessentially British than CDP. It may have taken its cue from Bill Bernbach's wry and ironic US work but its output was a very anglicised version of it. And it took UK advertising by storm.
CDP opened its doors on April Fool's Day 1960 when Britain was in the midst of huge social change. Agencies were becoming attractive places to work for people from all kinds of social backgrounds.
None more so than CDP, which not only had a very clear idea about the work it wanted to produce but was prepared to pay top dollar to those capable of creating it.
The agency was born when Ronnie Dickenson, a former ATV programme controller, and his friend, John Pearce, the managing director at Colman Prentice & Varley, offered to buy Pictorial Publicity, a tiny shop owned by John Collett.
Pearce was CDP's unlikely driving force. An eccentric, hard-drinking ex-Army officer, he hadn't entered advertising until he was in his fifties. Yet he was very clear about the kind of agency he wanted. And advertisers could either take it or leave it. He once fired Ford, then CDP's biggest client, because it kept trying to change the ads.
What's more, in Colin Millward, the creative director, Pearce had not only an outstanding talent spotter but someone who shared his values. He once famously told a Harvey's Bristol Cream account executive who'd had the temerity to agree some copy changes with the client: "Off you go, back on the train to Bristol. Tell them we make the ads, they make the sherry."
Pearce's regime was one in which anarchy prevailed, talent was indulged and emerging young directors - Ridley Scott and Hugh Hudson among them - were hired to bring the ideas to life.
It was the hell-raising Alan Waldie who came up with the Benson & Hedges "gold" campaign that was to take UK advertising to a new level; Paul Weiland was the sparkplug for Fiat's "hand built by robots" commercial, created to fill an entire News At Ten ad break.
It was also CDP that gave a young copywriter called Alan Parker his first taste of directing, including the Cinzano campaign starring Joan Collins and Leonard Rossiter and the Parker Pens film in which the finishing school teacher Penelope Keith teaches her girls "how to spend daddy's lovely money".
So how did an agency once the best in Britain fall so far? Frank Lowe's breakaway to form Lowe Howard-Spink in 1981, taking a number of clients with him, started the downward spiral. And when Dentsu bought into CDP, which then handled one of its key clients, Toyota, in the UK, the agency promptly lost the business to Saatchi & Saatchi.
Attempts were made to halt the slide. David Jones arrived from Lowe as the chief executive and fired a third of the staff before returning to his former home; Ben Langdon's appointment as the managing director resulted in a number of wins - Honda, Allied Bakeries, Courts and Littlewoods among them - but the agency failed to lock them in.
By 2001, CDP had ceased to be a separate entity when Dentsu, having by now assumed full ownership, merged it with travissully in which it had a majority stake.
Since then, the combined operation has been virtually anonymous. The agency handled the UK launch of the Yakult health drink but struggled when major pieces of business, such as the Switch debit card, departed.
Its predicament was made worse because Dentsu was unable to divert business into its UK outpost. "Japanese companies working with Dentsu in Tokyo won't automatically appoint a Dentsu agency in Europe," a source explains. "It just doesn't work that way."
That, though, may be about to change. Not only is Dentsu eager to crack the global market but it needs a credible presence in London given the probable involvement of some of its clients with the 2012 Olympic Games.
With Fallon's Andy Lockley now in creative command, is the Cinderella agency that used to be synonymous with having a ball about to return to it?
CDP'S HALL OF FAME
Tony Brignull - One of the best copywriters of his generation and a product of CDP's golden days. Went on to be DMB&B's creative director before retiring from Abbott Mead Vickers BBDO in 1994.
Ron Collins - Famously persuaded Joan Collins to star alongside Leonard Rossiter in CDP's series of ads for Cinzano. Later a founding partner of WCRS.
Graham Fink - Cut his teeth as a junior creative at CDP before making his name at Saatchi & Saatchi. Now M&C Saatchi's executive creative director.
Sir Frank Lowe - Joined CDP as an account handler but rose swiftly through the ranks to become the managing director. Later founded Lowe Howard-Spink. Now a partner at The Red Brick Road.
Sir Alan Parker - Copywriter with a no-nonsense style who had hopes of becoming CDP's creative chief before stumbling into directing.
Lord Puttnam - Spent five years as an account executive at CDP, which he later described as "my equivalent of university". Went on to produce movies such as Chariots of Fire.
Charles Saatchi - CDP gave Charles his third copywriting job. However, he was horrified by the laid-back atmosphere and determined not to replicate it at Saatchi & Saatchi.
Alan Waldie - Creator of the mould-breaking "gold" campaign for Benson & Hedges. Proved that restrictions didn't necessarily curb creativity but could stimulate it.
Paul Weiland - Along with Dave Horry, Weiland created the iconic "hand built by robots" commercial for the Fiat Strada. Went on to become one of Britain's most prolific commercials directors.
Robin Wight - Spent early years as a CDP copywriter. "Almost everything I learned in advertising, I learned at CDP," he says. Went on to set up WCRS with partners who included CDP's Ron Collins.