'Substantial' sinkhole closes prison building

Parts of HMP Norwich date back to the Victorian times

A prison building remains cordoned off after a sinkhole appeared, the Prison Service has said.

It was discovered in an administrative area of HMP Norwich during restoration work in August.

Steven Searby, chair of the Prison Officers Association union at the prison said repair work had been carried out on the "substantial" hole and that it took two applications of concrete to fill, as the first lot "just disappeared".

A Prison Service spokesperson said there was "no risk to safety or impact on capacity".

Mr Searby said the sinkhole measured about 1.5m (5ft) by 1.5m.

"Being from Norwich we know that sinkholes appear, like the double-decker bus in the 80s," he said.

"I know for a fact the one at the prison has been refilled."

Mr Searby said structural engineers had assessed the hole and that its depth was their "biggest concern".

A Prison Service spokesperson said: "The issue will be rectified as part of ongoing refurbishments."

HMP Norwich was built in the 1880s and has served solely as a male prison since 1924.

According to the British Geological Survey, Norwich is susceptible to sinkholes due to old chalk mines, which intercept "otherwise stable, sediment-filled voids".