In new advice, building owners are being told to sample test panels for combustibility where there is no documented evidence of fire resistance.

Problems with spandrel panels came to light in the inquest into the Lakanal House building fire which killed six people in 2009.

Spandrel panels used in the replacement window assemblies during building refurbishment were not rated Class 0 for surface spread of fire, and were deemed to have allowed the fire to jump into surrounding flats.

The Government is currently undertaking detailed work to assess the risks associated with these and other types of panels around windows.

Until these findings are published its expert panel is advising building owners to remove spandrels where they are assessed to be unsafe.

In the latest formal guidance issued yesterday, the Government has called on owners to seek information about the panels from design specifications and building records.

It also warns to check that product substitution has not taken place onsite.

The guidance states: “Where the panel product type can be confirmed building owners should check the fire performance with the manufacturer by requesting test certification.

“Where there is no information about the panel or there is uncertainty, it will be necessary to investigate the panel composition by sample testing.

“Building owners should seek professional advice and take precautions to avoid releasing hazardous materials such as asbestos which may be present.

“The expert panel’s view is that for buildings over 18m, the clearest way to ensure they do not present a risk of fire spread is to confirm that materials are limited combustibility or better.”