Anyone for a pair of Union Jack knickers?

Christopher Wren reckoned public architecture the ornament of a country. By that token, a country's embassies abroad must surely be the architectural equivalent of those almost useless but somehow typical offerings we take with us to give to foreign hosts. For we British it might be gift packs of tea and marmalade or a bottle of Scotch whisky, or, if we are more frivolous, a plastic policeman's helmet or Union Jack knickers.

Christopher Wren reckoned public architecture the ornament of a country. By that token, a country's embassies abroad must surely be the architectural equivalent of those almost useless but somehow typical offerings we take with us to give to foreign hosts. For we British it might be gift packs of tea and marmalade or a bottle of Scotch whisky, or, if we are more frivolous, a plastic policeman's helmet or Union Jack knickers.

The new British Embassy in Berlin, opened this week by the Queen, is an unusually extravagant offering in this class. But it is not in a class of its own. It is one of two dozen new embassy buildings just opened, under construction or planned for the new capital of Germany. Like a wedding gift from a close but somewhat estranged relation, ours manages to be both lavish and slightly tasteless.

The stakes are high for several unique reasons. First is the sudden elevation of the city to capital status, firing a starting gun for every country to relocate its ambassadorial offices. Second is Berlin's curious status as a capital coming out of mothballs. When West Germany was governed from Bonn, many prewar embassies in Berlin simply fell into ruin - ruins so picturesque that there was even a book of moody black-and-white photographs of them published in the 1980s. Third is the sheer pitch of the architectural bacchanal going on in the city as a whole, characterised by the massive commercial development, masterplanned by Renzo Piano, of Potsdamer Platz, the pre-war heart of the city. In the administrative sector, Norman Foster's glass-domed Reichstag is only the egg-shaped tip of the iceberg for a complete set of government offices nearby, designed by a team of respectable but unexciting German architects.

The embassies, given the same opportunity to start afresh, offer a potential cultural bonus with the chance to become concrete ambassadors for their countries. Some nations have chosen Berlin architects, but most have not missed the opportunity to show what one of their own can do. On the south side of the Tiergarten, Hans Hollein has designed a shiny metal teardrop of a building for Austria. Rem Koolhaas has designed a new Dutch Embassy.

East of the Brandenburg Gate, in the formal part of the old city, is where most of the big embassies reside. Soon, Christian de Portzamparc's new French embassy will rise on Pariser Platz--a white and glazed sheer façade, cut by diagonal concrete mullions, rather reminiscent of 1960s Corbusier. Facing this will be the new American Embassy, but its architect, the postmodernist Charles Moore, will only get to work once a dispute with the city authorities over the size of the surrounding security zone has been resolved. Neither country has fielded its best talent for the occasion.

Those countries which once sided with Hitler are pursing a different line. Having then been treated to plum sites overlooking the Tiergarten, Japan and Italy built grand fascistic villas in a severe classical style. Both countries are now restoring these edifices, rather than building anew, apparently unconcerned for the political subtext that architecture reveals. Most of the former Warsaw Pact countries are staying put, too, along Unter den Linden in what was East Berlin.

It is the presence of a troubled past that challenges architects. There have been other new capitals, but who can recall the names of embassy architects in Canberra or Brasilia? As for London, there is simply no heading for "Embassies" in the architecture guides. The only notable ones are the Danish Embassy, oddly like a piece of precision engineering on Sloane Street, and some playful concrete work for what was once the Czechoslovak Embassy on Bayswater Road. Then there is the American Embassy, bombastic yet dreary, described by Christopher Woodward as having the look of "a large department store rather than the pomp and circumstance appropriate to an Embassy".

The renaissance of Berlin is symbolic not only of German reunification but also of the new age of non-ideology, and, fortuitously, it comes at a time when architecture has become a cultural commodity. The resulting buildings are able as never before to show their various nations as they wish to be seen, but they perhaps also reveal aspects that some would rather keep hidden.

What is one to read, for example, from the façade presented to the street, just off Unter den Linden, by the British Embassy? It is dominated by a heavy stone façade, 22 metres high - ostensibly respectful to the neoclassical architecture of Karl Friedrich Schinkel, who dominates so much of Berlin, and who was a hero for Wilford's late partner, James Stirling. From a first-storey slot cut into this forbidding front project are a number of coloured blocks: these are our toys, but you can't play with them, seems to be the message to the passing asylum seeker. It is underlined by the heavy gate, omitted from the architect's early drawings and models, and the sentry post behind it, reminiscent of another Berlin. Thankfully, the architectural equivalent of the Union Jack knickers - horizontal and diagonal crosses incorporated into the structural frame of the building - is only visible from the internal courtyard.

A warmer welcome comes from the Nordic countries. Denmark, Sweden, Norway, Finland and Iceland clubbed together - itself an indication of new attitudes to nationhood - to produce a demure campus of crisp, unthreatening, but unequivocally modern embassy buildings. Five wedge-shaped units, all sharing the same roof line, face in to a small stone courtyard near the Tiergarten. They generously gave the job of a small communal visitor centre to an outsider, the Austrian partnership of Alfred Berger and Tiina Parkkinen. All six buildings are wrapped in a sinuous screen wall of pre-patinated rectangular copper scales like a green scarf.

The obvious game is to guess, using one's knowledge of the geography, economics and culture, which embassy is which. (There is a discreet crib sheet nearby, but on the buildings themselves no obvious clues except a rather lurid crest for Denmark.) It's surprisingly easy. The Danish Embassy (Nielsen, Nielsen and Nielsen) is clad in perforated oblong steel panels with the ubiquitous Danish proportions of a Bang & Olufsen stereo or a Stelton coffee pot. The Swedish (Wingårdh Arkitektbyrå) is the other technocrat's delight, in glass and polished black and white stone. Norway (Snÿhetta) and Finland (VIIVA) adopt frosted green glass and larch wood louvres respectively. Iceland's (Pálmar Kristmundson) is the one sheathed in volcanic stone.

Whereas Wilford speaks of the "dignity and grandeur" of his interior of the British embassy, for these countries modesty is allimportant inside too. The selfeffacement is so total that this little cluster of buildings might almost be an ironic joke. Staff of all five buildings even share the same small, plain wooden entrance door.

There is another game you can play with this parade of new buildings: given a free choice, which would you have represent your citizenship? The great German architect and Bauhaus supremo once remarked: "A modern, harmonic and lively architecture is the visible sign of an authentic democracy." The remark stands not only as a measure of Berlin at the dawn of the new millennium but as a yardstick by which to evaluate the city's new embassies and the countries they represent.