The campaign to rebuild Euston Arch is not nostalgia, Jonathan Glancey argues. It would right a great wrong and symbolise a new railway era

The destruction of the Euston Arch in 1962 was a cathartic event. It signalled the wholesale redevelopment of central London (and other cities) with crass, fast-buck, shoe-box architecture that, pretending to be Modern, was simply greed tricked up in sky-high monuments of concrete and steel.

The Arch - a vast Doric propylaeum designed by Philip Hardwick as the gateway to the new London and Birmingham Railway - was destroyed by express order of the then Prime Minister, Harold Macmillan. Quite what could be achieved by the demolition of this stirring monument is anyone's guess today. What is certain is that it need not have been demolished to build the bland, airport-style terminus that replaced the old Euston station in the mid-Sixties.

If the Euston Arch Trust (EAT) has its way, the Arch will make a triumphal return in the next few years. Founded by Dan Cruickshank, architectural historian, broadcaster and contributor to these pages, EAT has already made great strides. Railtrack is keen, the London Borough of Camden has no case against the revival of the Grecian monument, and there are numerous wealthy railway enthusiasts who may well be willing to help to meet the cost - estimated by EAT at little more than pounds 3m.

The BBC has already filmed the trustees of EAT pondering the road ahead for its One Foot in the Past series, while discussions of what use the arch should be put to and how it should be rebuilt are well under way.

A new use is not obvious, as the arch concealed a large, top-lit office behind its massive stone pediment. Reached by a narrow spiral staircase, this was used by the arch's successive owners (the London & Birmingham, London & North Western, London Midland and Scottish railways and the London Midland Region of British Railways) before demolition. What might it house now? A museum? An archive? A giant model railway?

The other key question is how will the arch be rebuilt? As Cruickshank discovered two years ago, many of the stones are still intact, lying on the Thames riverbed at Bow Creek and in the gardens and ponds of the men contracted to demolish the arch 33 years ago. To raise them would, however, be expensive and difficult, even though the stones themselves are in remarkably good condition. It is probable that the reconstituted arch would be an amalgam of old and new.

The campaign to rebuild the arch is not simply a case of nostalgia. The trustees of EAT include such overt Modernists as Peter Smithson (responsible for the Economist building in St James's), and its architect is Piers Gough, well known for his colourful and characterful new buildings. What the trustees believe is that the rebuilding of the arch is an opportunity to put right a historical wrong and a chance to pull together the fragmented townscape of the busy Euston Road - and possibly the recreation of Euston Square, remembered in the name of a nearby Underground station, but invisible to passers-by. Most of all, the arch will act as a grand and symbolic gateway to Euston station. For railways have entered a bright new age, and the rebuilding of the arch can only help to reconnect a noble past with a dynamic future.

The RIBA/Independent programme of public lectures on architecture in service of the public realm continues this autumn. The subjects for discussion are:

The future of the Grand Midland Hotel and St Pancras station;

How good new architecture can regenerate forgotten areas of the city;

The relocation of the ICA from the Mall to a bridge across the River Thames; and

A long-term strategy for the Thames itself.

Wednesday, 25 October, Jonathan Glancey on St Pancras

Thursday, 2 November, Piers Gough on new hearts for old cities

Thursday, 16 November, Will Alsop on the future of the ICA

Thursday, 14 December, Richard Rogers on a strategy for the Thames

All lectures start at 7pm, Jarvis Theatre, Royal Institute of British Architects, 66 Portland Place, London W1N 4AD.

Tickets are pounds 4 (pounds 2.50 students and concessions), available from the RIBA Bookshop by credit card booking on 0171-251 0791, or by cheque to the RIBA Architecture Centre at the above address.