From 1621 the records of the House of Lords had a permanent home within the Jewel Tower. A small inner room on the first floor was used, and a brick vault (which still exists) with an iron door was erected in place of the former wooden ceiling to serve as fire-proof storage.
By the Restoration, the Tower had become the accepted home of these records, besides acting as what was called the Parliament Office for Clerks to compile the records of various sessions and committees.
Repairs to the Tower
In 1716, the Clerk of the Parliament filed a petition complaining that the condition of the Tower was detrimental to the records. A committee was appointed to view the Tower. It concluded that the Tower should be speedily repaired, and recommended that two additional rooms be renovated to house the ever-increasing records.
By the time the works were finished in September 1719, the costs of renovation had mounted to £1,118, and their effect was to leave the Tower much as it is today. In 1800, the Records Commission reported that they found the records in the Jewel Tower in good preservation and methodically kept and arranged.
As the Tower was built into the palace's defensive walls but was detached from the main buildings, it survived the great fire of 1834. This was crucial to the preservation of records such as Charles I's death warrant.