A DETAILED study of the Wellington Monument was carried out at an open day on Sunday when 100 people met with experts from the National Trust and their contractors.

A specialist team had been brought in to use ground-penetrating radar on all three faces of the obelisk to give a detailed picture of the structure under the stone cladding.

The team abseiled down the 174ft high tower with the equipment to undertake the first detailed survey of its type on the monument.

On hand to meet the public was Ken Evans, the National Trust building surveyor who is in charge of the investigations.

He said: “This is the latest in a detailed set of monitoring studies we are carrying out to understand this unique and somewhat complex monument.

We have been using wind and movement sensors which have already surprised us by showing that it doesn’t flex in the wind quite as much as we expected.

“The ground-penetrating radar seeks to identify voids and gaps in the stonework under the surface but should also tell us more about the materials which were used to build the obelisk.”

The National Trust commissioned the work, which also involves experts at Southampton University who will process the data and build it into a computer model.

“The modelling work will help us to identify where the stresses and strains are in the structure and will be crucial to explore repair options needed to secure the future of the monument,” added Ken.

The monument, built as a tribute to the Duke of Wellington at the Battle of Waterloo in 1815, had to be closed by the Trust and fenced off because of falling stone debris.

Visit nationaltrust.org.uk/wellington-monument for more details.