Brownsea Island, Dorset

Brownsea Island is the largest island in Poole Harbour, which was a major port in the Iron Age. Despite this no Iron Age material has yet been found on Brownsea Island itself. In 1964 an Iron Age log boat was discovered just off the island and is now on display in Poole Museum. 

Off the north-east coast, a Romano-British site was discovered in 1973 around 80m from the sea wall, however it is thought that the site has since been destroyed by tidal action. 

Evidence of a medieval chapel and medieval salt production on the island have been found, but it is from the post-medieval period onwards that the majority of features date. In 1548 a blockhouse and gun platform were built as part of Henry VIII’s network of coastal defences. In 1726 it was converted into a country house and has since undergone numerous extensions and re-modelling.

In the 16th and 17th centuries the island was used in the copperas and alum industries. Brick structures, kilns and possible evaporation tanks have been identified and recorded in the past although they may not remain as they are actively being lost to due to erosion. 


CITiZAN Brick Kiln, Brownsea Island by maritimearchaeology on Sketchfab

In the 18th and 19th centuries the island contained a large pottery industry. The 19th-century Pottery produced earthenware; the complex was connected by a tramway which ran across the island. Maryland village was built in 1855 for the pottery workers; they were later evicted in 1929, and the site fell into disrepair. After a subsequent fire and WWII bombing, the site was demolished in 1963. An associated rubbish dump is eroding from the nearby coast and the remaining footings of the village are now just 20m from the beach. The buildings along the quay were originally coastguard cottages built in the 1840’s, and along with the castle are now listed.

The island's strategic position at the entrance of the harbour meant it continued to be used for defence. A coastal battery was built in the 19th century and later adapted in the 1940’s. During WWII the island was also used as a decoy site. 

Much of the work through the CITiZAN project has focussed on the southern shore where a brick kiln and two other features are being lost to the sea. The brick kiln, also known as Barnes Brick Kiln has also proved a useful case study to see how effective 3D modelling is in the rapid recording and monitoring of coastal and intertidal features. Three models have now been made of the kiln over the course of three years and the team are in the process of comparing these to see what quantitative data can be obtained in order to assess how much of the site has been lost and at what rate. 

Two other features further west along the southern shore include a 3m long cut in section eroding from the cliff thought to relate to a brick kiln and a 3m wide brick lined pit with vertical sides and a flat base. These two features are being rapidly lost and were therefore used as part of a CITiZAN training event with National Trust volunteers, during the event the team learnt how to undertake an offset survey which resulted in two section drawings of the features. These can now be compared with previous surveys to look at change over time and can be used to preserve the sites through record. 

Kiln eroding out onto the foreshore at Brownsea Island
Kiln eroding out onto the foreshore at Brownsea Island

As well as work on the fragile and dynamic southern shore, the CITiZAN team have also been looking at intertidal remains on the north shore. A very different environment this shoreline is managed by the Dorset Wildlife Trust as a conservation area. The remains are part of the 19th century pottery works and consist of several shafts which were used to prospect for clay. Originally it was thought that the island contained large amounts of the valuable 'ball clay', a very fine white clay capable of making fine tablewares. However, unlike clay pits on the nearby mainland which were extracting huge quantities, Brownsea only contained small pockets and the clay which was easily accessible was only good for basic domestic wares, such as drainage pipes. 

In 2017 the CITiZAN team plotted and photographed the clay shafts, some of which run up to 60ft deep and even go out under the harbour itself. These shafts were connected to the main pottery works with a tramway. 


One of eight shafts on the northern shore of Brownsea. 

As well as the clay shafts there are also the remains of several clay pits which were dug into the small cliff and on top of the cliff is Seymers Cottage. Now in ruins and rapidly deteriorating, this cottage was actually built before the pottery works were established. It is thought to have been built by Sir Charles Chad who owned Brownsea Island between 1817 and 1840, according to documentary evidence it would have had a verandah and beautiful views north across the harbour and back across the island, although this is now blocked by trees. The cottage also has a rather unique circular privy which still survives today! A blog about the site has been written by National Trust archaeologist Martin Papworth. 

If you would like to find out more about the features we have been recording or wish to submit your own survey on the remains then visit our interactive map:

Barnes Brick Kiln

Brick Lined Pit


Clay shafts

Seymers Cottage