David Trench, the project director on the Millennium Dome, knows from experience what happens when people stray too far from a project’s initial raison d’être

concepts are born out of need, and commercial developments are no exception to this rule. To take three high-profile examples: the British Library was conceived to properly conserve the nation’s stock of 15 million literary artefacts; the Millennium Dome expressed a need by the then Conservative government to celebrate the millennium; the old Wembley Stadium was looking tired and unattractive, thereby offering up the stark alternatives of falling attendances or comprehensive redevelopment.

The fact that they are answering a specific need, however, does not mean that concepts cannot go badly awry. Massive decisions are made at the point in time when the least information is to hand – for example, “Shall we redevelop or refurbish or shall we relocate?”

For this reason, it is absolutely essential that the initial ideas are subjected to rigorous testing and that the business plan is robust at the outset. The vital things to get right are: timing, location, future market, competition and changes in technology. This is where two of the three projects mentioned earlier came unstuck. Only time will tell on the third.

The British Library

The Trustees of the British Museum employed Sandy Wilson to start work on their concept in 1962. It opened in 1998. The final the bill to the taxpayer was £519m.

In this long gestation period advances in technology allowed the complete works of Shakespeare to be stored on a pin head.

By the library’s completion, CDs and laptops had become the fastest forms of storage and retrieval. It is not a lending library. One might question the whole raison d’être of 340 km of shelving and an automated book-handling system serving four massive basement underground storage areas.

Equally, one could not pick a more polluted site in London in respect of diesel emissions than the library’s location next to Euston, King’s Cross and St Pancras stations, and the congested Euston Road. Yet they did, despite the fact that it costs more than £1m to change the carbon filters on the air-conditioning system – the largest single site system in the UK.

The Millennium exhibition

Massive decisions are made at the point in time when the least information is to hand – "Shall we redevelop or refurbish or shall we relocate?"

When design consultancy the Imagination Group stunned the Millennium Commission with its presentation of an exhibition based on time zones, the concept had a central theme and was designed to take place at the National Exhibition Centre in Birmingham.

The move to the Greenwich peninsular, masterminded by Virginia Bottomley and Michael Heseltine, had a profound effect on the budget and put a stake through the heart of the Imagination scheme.

The political decision to hold the exhibition in the capital entailed having to spend millions on decontaminating a site that had formerly been occupied by one of the largest gasworks in Europe. Electrical power had to be brought in from West Ham via seven miles of secure tunnel, and that was all before the cost of the Dome itself. Additional infrastructure took £200m out of a budget already arbitrarily reduced £250m by Jack Cunningham during the run-up to the 1997 election. Inevitably, the exhibition’s content had to be dumbed down to pay for things that had no spectator value.

Unfortunately, the exhibition needed to be pretty fantastic to lure people to an off-centre location like Greenwich. EuroDisney took seven years to attract 10 millions visitors per year. Was the concept of operating for one year and basing a business plan on 12 million visitors ever viable?

Wembley Stadium

I have the greatest difficulty with the Wembley Stadium project in endorsing the notion that the 1000-seat banqueting facility and other substantial dining facilities will ever be regularly used outside international football matches. Every sporting venue in the country has tried to come up with ways of earning additional revenue from its under-utilised facilities. Yet few have succeeded in justifying the capital outlay, let alone the running costs, of facilities built to the standard needed to attract the corporate conferencing market.

Wembley is neither fish nor fowl, in so much as it is neither central London nor in the heart of the Countryside, and some way off the M25. Given the better located competition, surely the FA has been hoodwinked into making the huge investment being ploughed into conference facilities in such a location …