London doesn’t normally ‘do’ entrances, or at least we don’t anymore. Medieval citizens loved them and throughout the Middle Ages the boundary of the City of London was littered with gated entrance-points.

Neo-classical visionaries revived the idea on a grander scale in the early 19th century with Hyde Park Corner and the now vanished Euston Arch both partially conceived as grand, ceremonial entranceways into the city. But nowadays, the closest we are likely to get to one is a sign on the M1 saying ‘Welcome to Barnet’. Hardly inspirational!

Which is what makes the current London Festival of Architecture exhibition in St. Botolph’s Church in Aldgate so intriguing. Organised by the Architecture Foundation and the Worshipful Company of Chartered Architects, it features competition entries for a temporary new City entrance to be constructed in Aldgate in 2012. It will mark the start of what has been dubbed the ‘Olympic High Street’ which will eventually end at the Olympic Park itself in Stratford. Five entries have been shortlisted and the winner will be revealed on the 22nd July.

As well as providing an innovate means to ensure that the Olympics exerts a urban impact far beyond the Games site, the competition has invited designers to re-interpret historic notions of ‘triumphal’ gateways and produce a contemporary landmark that represents London, the Olympics and – crucially – Aldgate itself.

With its hostile commercial architecture and tortuous, traffic dominated one-way system, Aldgate has been long derided as a symbol of failed 1960s planning. However, it is currently undergoing a period of significant change, with a partially re-aligned traffic layout and new developments promising a renewed public realm and a more hospitable urban character. All the proposals clearly seek to tap into this new, more aspirational future.

However, they also evidently wish to engage in Aldgate’s rich and varied past, particularly its historic role as the City’s oldest mediaeval gateway and the only entrance that admitted all citizens. Etymologists have variously claimed that the origins of the district’s name derive either from the Old English versions of ‘Old-gate’ or ‘All-gate’. It has also always straddled the point where the wealthy City meets the poorer East End. This wealth of symbolic reference therefore has provided the conceptual impetus for many of the designs.

The fourteen proposals certainly provide a diverse visual and sensual palette with some offerings more surreal than others! Biota’s ‘State of Aldgate’ proposes illuminated vertical columns on a traffic island that forms an interactive “mediascape” that pedestrians will be able to temporarily claim as their own sovereign state. The idea is joyfully reminiscent of Ealing Studios’ classic comedy, ‘Passport to Pimlico’! ‘London Gate’ by Donis – shortlisted – proposes a 100 x 12m “naked tower” where a glazed viewing platform will move vertically within a simple steel frame.

‘Listening Post’s by Foster Lomas proposes vertical acoustic posts that will produce an “island of sound”. ‘Aldgate to the World’ by Juan Alfonso Galan Arquitecto is described as an “audio visual icon” that features a tall, solari-type flap destination board that relays various geographic, demographic and physiological information about Aldgate to the outside world. Both schemes are shortlisted.

Casson Castle Architects, Sandy Render Architects and Structure Workshop have proposed a utilitarian archway grandstand that, by allowing people to sit directly on the structure, democratises the traditionally exclusive notion of a ‘triumphal arch’. And “Vertical Forest” by Sou Fujimoto Architects – shortlisted – offers a slender cylindrical tower that is garnished with fulsome greenery and foliage.

All the schemes display a key element that is often lost in architecture – fun. They provide a means to relate to the history and symbolism of the city and local neighbourhood in a manner that is informative and contemporary yet celebratory also. Modernism, with its uncompromising emphasis on form following function, gave ornamental architecture a tough time. If decoration was out and symbolism could be conveyed in abstract rather than literal terms, what was the point of it? Well the point of it - as this exhibition so imaginatively proves - is to uplift and to inspire. And regardless of which entry wins, for one year at least, a formerly moribund part of London will reap the rewards.

’A New Landmark for Aldgate’ runs from 18th June to 14th of July in St Botolph’s Church, Aldgate High Street, London, EC3N 1AB. Opens 10.00 - 18.00 Monday to Saturday, 12.00 - 18.00 Sunday.