The document will contain letting arrangements, rents and the service charge. But the most significant aspect is that the market will only be able to house around two thirds of the existing 143 tenants. This has been accepted, in principle, by the tenants' association.

The development is the result of two years of intense negotiation between the council and Kier Developers (KD), since Western International Market Tenants Association (WIMTA) signed a 'co-operation agreement'. WIMTA has spent over £250,000 in legal and consultancy fees in that time, as well as a considerable amount of research time visiting other UK and continental markets.

Chairman George Bray is pragmatic over the reasons why the market will be smaller. He stressed that wholesaling has changed radically since Western tenants were rehoused at Heston, after moving from their Brentford site over 25 years ago.

'The large, nationally oriented companies that were once Brentford and Western tenants have either disappeared or re-sited as they evolved into packing and distribution depots for the multiples,' he said.

For this reason even the initial conception of the plan has not been a simple exercise, although HBC, WIMTA and KD have worked closely together to ensure that the new market fulfils the expectations of as many tenants as possible.

'Western has continued to survive because it is still a strong base for smaller dedicated family companies which have taken on other roles,' explained Bray. One example has been that while secondary wholesalers buying on the market have now virtually ceased to exist, the tenants have taken on this role themselves often combining this with serving and delivering to a booming food-service sector.

Additionally, it has created a special niche as a vibrant ethnic market carrying a wide range of speciality products from the Asian sub-continent.

'Nevertheless, there is still bound to be some natural wastage when we move,' he said. ' Our aim has always been to support the majority interest.' To qualify for the move tenants will be judged by Hounslow on their financial standing, rent record and usage, again agreed with the WIMTA.

While the market still has to receive planning permission, plans so far are for a single unit with an inward facing trading hall and buyers' walk. There is both a separate flower market and the addition of a food wholesale area.

The construction cost of the market itself is estimated by Graham Smith, the borough's property manager, to be some £15 million covered by the development of the old site on which 250,000-300,000 sq ft of non-horticultural distribution facilities will be built. 'It will have entirely different uses and appeal to businesses because of its location near Heathrow Airport,' said Smith.

Bray predicted that tenants will be operating more cold stores to meet the hygiene regulations required by their new breed of customers and work in modern, computerised offices linked on mezzanine levels. It will be a far cry from the present cramped mix of lean-tos and Portakabins and, he said, will have enhanced waste disposal.

But it will come at a price. The committee estimated that the collective cost of fitting out members' units would add a further £2.2m to the relocation bill.