Mainly because it was the sort of place where you could sample every type of fine, nutty, local ale while demolishing the world's best homemade meat pies.
Now, since its takeover by a large bar-owning chain, Whitelocks is apparently facing a makeover that will scrap its pie-and-ale culture and turn it into a "city day pub" for wine drinkers.
There's hope yet for Whitelocks because the beardies at the Campaign for Real Ale are lobbying for its continued existence as one of the best British pubs.
But is another great British institution, our fine media agency heritage, also in need of protection? I ask in light of WPP's takeover of Grey, which will also give it control of MediaCom. Surely there should be nothing to fear, because MediaCom has fallen into the hands of yet another fine British institution. Also, it was previously owned by the Yanks - and the MediaCom network was partly built by a German, chief executive Alexander Schmidt-Vogel - so xenophobes could argue it will finally get the care it deserves. But MediaCom UK is only one of a few agencies in the MediaCom network (such as those in Germany and the US) that can be described as strong and WPP must preserve this asset.
As others have pointed out (see this week's Media Forum) WPP has a silo-based approach to its brands and is committed to keeping the MediaCom brand. Its more immediate global concerns will be stripping out cost from the Grey group of companies, presumably MediaCom included, to improve margins. Growing MediaCom as a global network (it is ranked eighth and has glaring deficiencies in Asia and Latin America compared with its rivals) should also be a concern.
Turning back to the UK, MediaCom is reassured because its group structure remains in place - it will continue to operate as part of the Grey unit within WPP (its managers will report to Schmidt-Vogel, who, in turn, reports to Grey's Ed Meyer).
However, judging by WPP's preferred way of running media networks (separated totally from creative networks and reporting to media parent company Group M), it can only be a matter of time before MediaCom's link with its Grey parent is cut.
Few tears would be shed over this at MediaCom UK -mainly because most of its senior management are not from a Grey background - but WPP will have to be careful not to prune back the agency's culture when the inevitable dealings with Group M commence.
Rich's, the MediaCom staff bar, might not serve ale on a par with Whitelocks but it would be a shame to see it rebranded as Cafe M or the M Bar.