Public authorities engaged in nationally significant infrastructure projects have the power to enter private land to carry out necessary surveys. An important High Court ruling in the context of the proposed construction of a road tunnel near Stonehenge established that such works can involve far more than merely setting up a theodolite.

Highways England Company Limited (HECL) was developing proposals to replace the single carriageway A303 trunk road where it passes Stonehenge – a notorious traffic blackspot – with a tunnel close to the world heritage site. The tunnel would pass through a chalk aquifer running under a local farmer's land.

In order to design the tunnel – for which a development consent order (DCO) had been sought – HECL needed to undertake pumping works on the farmer's land. They would include the construction of monitoring boreholes and the pumping of water from a well which would have to be discharged onto the farmer's fields. The farmer claimed that the works would result in his land being inundated by about 45 million litres of groundwater, causing serious damage.

The Secretary of State for Housing, Communities and Local Government granted HECL authorisation under Section 53 of the Planning Act 2008 to enter the farmer's land to carry out the required works. After receiving advice from the Planning Inspectorate, he found that such access was genuinely required. Following unsuccessful negotiations, however, HECL gave notice that it instead intended to exercise its power under Section 172 of the Housing and Planning Act 2016 to enter the land and complete the works.

Challenging that decision, the farmer's lawyers argued that, having chosen to take the Section 53 route to authorisation, HECL could not change its mind and instead rely on its broader power under Section 172. The Section 53 procedure was related specifically to the DCO process and was subject to safeguards, including the requirement for the Secretary of State's approval, that did not apply to Section 172.

In ruling against the farmer, however, the Court found that Sections 53 and 172 are overlapping provisions and that HECL was entitled to take either route to its objective of gaining access to his land. As strategic highway authority for the A303, HECL lawfully chose to exercise the power of acquiring authorities under Section 172 to enter and survey private land in order to pave the way for nationally significant infrastructure projects.

There was considerable force in the farmer's argument that the extensive works would stray well beyond what could be described as a survey. However, the Court concluded that the discharge of large volumes of water onto his fields would be part and parcel of the required pumping tests and that the works in general fell within the definition of a survey authorised by Section 172.