Four boreholes were drilled into the ground as part of a ground survey, in preparation for a controversial £3m redesign.

Father Timothy Lipscomb, chairman of the Friends of Avenham and Miller Park, said: "This work is necessary because without it, the underground conditions would be an unknown quantity."

They hope this will result in a better drainage system for the scheme.

The work is being carried out to allow Cooper Partnership - winners of the redesign competition - to put forward a planning application to Preston City Council as the next` part of the project.