Southwark Council and six other London boroughs have taken their fight to save 10 fire stations in the capital to the High Court.
Camden, Greenwich, Hackney, Islington, Lewisham, Southwark and Tower Hamlets councils have now made an application for permission to apply for a judicial review of the decision by the Mayor of London, the London fire commissioner and the London Fire & Emergency Planning Authority to make cuts to London's fire and rescue service.
The application was issued on Thursday 3 October at the Royal Courts of Justice.
The councils also applied for an injunction preventing the cuts programme from being put in place until the judicial review application has been considered.
"This application is a huge milestone in our fight against these cuts to our fire service, and I hope everyone now knows that we mean business," said Cllr Richard Livingstone, Southwark's cabinet member for finance, resources and community safety.
"In Southwark, we have experienced the highest level of fire deaths of any London borough over the last five years and that is why we cannot sit back and watch this vital service diminished – our residents deserve better."