Transport secretary Stephen Byers approved the scheme on Tuesday, ending the longest planning inquiry in UK history.
Airports operator BAA must comply with a number of conditions before the main scheme can start on site. These include obtaining separate approval for the diversion of two rivers that cross the T5 site.
Other conditions stipulated include the completion of extensions to the Heathrow Express train route and the Piccadilly Line underground service.
BAA said it expected the terminal would be open by 2007 – 14 years after it first applied for permission.
A spokesperson for the airport operator said the project team was examining the conditions, especially the need for the diversion of the rivers. "That needs a lot of thinking about – especially if we cannot start any work until it is resolved."
He added that the scope of Richard Rogers Partnership's design may have to be tweaked. "The team has been working on the designs for many years. It has a plan A, but the question is whether it can be executed under those conditions."
BAA is also to meet UCATT, the T&G and the GMB unions next month to discuss direct employment and health and safety issues.
BAA said in February that it would project manage the scheme itself and was forming a management team for that purpose. This will include BAA staff as well as key framework contractors and consultants. One team source said he expected a major project planning meeting to be held soon.
he added that he BAA would probably split the project into packages, such as infrastructure work, new-build and fit-out.
The source said: "BAA will probably adopt a horses-for-courses attitude, dividing it into different elements."
Main BAA suppliers include contractors Amec, O'Rourke and Laing, engineers Mott MacDonald and Arup, QSs EC Harris and Turner & Towsend. Pascall + Watson is lead detail architect on the scheme.
The design team is set to double this year from 200 to 500-600, and an initial workforce of 2000 will be required if work starts next year.
The T5 saga
- The four-year, £80m public inquiry into the T5 development concluded on 17 May 1999 and was the longest of its kind in the UK.
- The proposal sparked fierce opposition from residents and environmental groups. Demonstrators held a rally outside the BAA annual general meeting in July this year, and occupied the BAA boardroom in August for five hours before being removed by security staff.
- The official inquiry report, landed on ministers’ desks in December 2000 – the scheme was approved 11 months later in November 2001.