A 'Brownfield' site is an area of land that was previously developed, often but not always for industrial and commercial purposes. It may be contaminated - asbestos may lay buried.
If you need to find out whether you are on a brownfield site, ask your local authority planning department.
Before digging on a brownfield site, it is good practice to sample the ground first. Any suspicious material requires analysis for asbestos. And even if no asbestos is found in the sample, the excavation may still reveal suspicious material.
Where suspicious material is found, the contractor should:
The contractor must not back-fill with asbestos material.
You should arrange for a surveyor or testing laboratory to take samples. Don't try to do this yourself. It is good practice to use UKAS-accredited organisations.
You might need an HSE-licensed asbestos contractor to complete the job: ask an asbestos surveyor. Spoil that contains asbestos needs safe disposal.