How to look for records of... Patents of invention

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1. Why use this guide?

This guide tells you how to find The National Archives’ original records of patents of invention, and any related specifications, issued between 1617 and October 1852.

You may prefer to buy printed copies of these from the Intellectual Property Office. You will need to know the patent number and year of issue.

Patents and specifications issued after 1852 are not held at The National Archives and in general these records do not survive. You can, however, search for inventor names or subjects through the Intellectual Property Office.

This guide also tells you how to find other records relating to patents from the late 16th century onwards.

2. What are patents and specifications of inventions?

Inventors can get an exclusive right to manufacture their own inventions for a limited period. The state issues ‘letters patent of invention’ and also enrols them to record this right.

Initially the inventions were not described, but over the next century they were increasingly described in detail until this was almost routine. From 1711, specifications (providing full working details of the invention) began to be enrolled in a different place after the issue of the patent. By 1734, they were almost compulsory.

Up to October 1852 the Court of Chancery was responsible for the enrolment and issue of patents of invention, and the enrolment of specifications, safe-guarding intellectual property rights in England and Wales.

The Patent Office (now the Intellectual Property Office) took over this responsibility when it was founded in 1852.

Read more about the history of patents or see information on searching for historical patents on the British Library website.

3. Finding patents of invention 1617-1852

To look for a patent of invention issued between 1617 and October 1852, you need to start with the printed indexes, available at The National Archives, the British Library and in several reference libraries.

These were published by Bennett Woodcroft as a six-volume work called Patents of Invention: from March 2, 1617 (14 James I) to October 1, 1852 (16 Victoriae) (Queen’s Printing Office, 1854-1855) in four sequences:

  • alphabetical index, of inventors
  • subject index, of inventions
  • chronological index
  • reference index: publication details, and enrolment details

From these, you can pick up the reference number and the year (for example, Electric batteries, Reference Number 12,697, Year 1849) and buy a printed copy from the Intellectual Property Office.

Search Google Books using keywords ‘Bennett Woodcroft’ to find copies of some of these indexes online.

If, however, you want to look at the original enrolments of both patents and specifications, these are kept at The National Archives.

4. Finding enrolments of patents of invention issued up to October 1852

Patents of invention are enrolled, along with many other types of letter patent, in the patent rolls in C 66. These only have contemporary indexes, in C 274 (available in the Map Room at The National Archives).

First take the year and month given in the indexes, and convert it into a regnal year (using the handbooks of dates in the Map Room).

Go to the annual calendars labelled ‘C 274’ in the Map Room at The National Archives, and find the right regnal year. These usually have some kind of index at the back, or the entries are arranged by initial letter of surname. Look for the inventor’s name.

Most have been marked up with the modern C 66 reference. If not, you will need to look at the C 66 list to convert it – instructions are provided.

You may find the book ‘British Patents of Invention, 1617-1977: a Guide for Researchers (British Library, 1999) by Stephen Van Dulken helpful.

5. Finding enrolments of specifications filed up to October 1852

The specifications were enrolled separately in any one of three Chancery offices. The copy of Woodcroft’s Alphabetical Index in the Map Room at The National Archives has been marked up with modern references for many specifications: if not, you need to follow the following steps.

Take the bold reference number from the Alphabetical Index, and look it up in the reference index. This will say (among other information) Enrolment Office, Petty Bag, or Rolls Chapel.

Convert this to a modern reference using the instructions below, which refers to volumes in the Map Room:

Enrolment Office

C 54: These are listed in date order in the volumes labelled ‘Refers to C 54 vols 164-166’, in the Map Room. Each entry gives the year and part number of the Close Roll on which the specification was enrolled – use the C 54 series list to convert this into a modern reference. Specifications for 1849-1853 are all in C 54 and are listed by date in the volume labelled ‘Refers to C 54 vol 161’.

Petty Bag

C 210: The Alphabetical Index has been marked up with all the modern references to C 210. Specifications are also listed by date in the volumes labelled ‘Refers to C 210 vols 1-2’. This contains an index of names in three sequences to match the three sections (‘calendars’) of the lists. Put C 210 in front of the ‘part’ number to get a modern reference.

Rolls Chapel

C 73 or C 54: Look at the volume labelled ‘Refers to C 54 etc, vol 163’. Try both the C 73 section and the C 54 section under the rough date (specifications were filed after patents). C 73 entries have the modern reference written in red. C 54 entries have to be converted, using the C 54 list.

6. Early patents of invention, with no specification

Most early patents give few details about the precise nature of the invention.

Try SO 7 from 1661. These bills, which authorised the issue of letters patent, sometimes include drawings of inventions.

Use the Reference Index, which has an appendix giving abstracts from some early (1617-1745) applications for patents, where no separate specification was enrolled.

7. Other records relating to early patents

You can find other types of records relating to patents before October 1852 at The National Archives. Search Discovery, our catalogue for keywords such as ‘patent’ or ‘invention’, restricted to departments BT, HO and SP.

Records include:

  • petitions for patents before 1782, with law officers’ reports, in State Papers Domestic. Search State Papers Online or use the entry books in SP 44
  • petitions for patents from 1782 onwards in HO 42, HO 44 and HO 45, with entry books in HO 43
  • warrants to law officers to draft patents of invention for 1783-1834 in HO 89
  • some reports by law officers, applications by patent agents and disputed cases, 1839-1885, in LO 1

8. Scottish patents up to October 1852

Scotland had its own separate registration system for patents before 1853. Go to the National Archives Scotland for the records.

However, The National Archives holds some relevant records in:

  • HO 105, relating to Scottish inventions, 1840-1855
  • HO 106, which can refer to inventions, 1774-1847

9. Irish patents up to October 1852

Ireland had its own separate registration system for patents before 1853, but the records no longer survive.

However, you can find some records at The National Archives which refer to Irish patents in:

10. Records after October 1852

Contact the British Library’s Business and Intellectual Property Centre if you want to identify UK patents from after October 1852. British patents from 1893 onwards are generally available on the Espacenet website.

You can search for recent patents (granted since 1992) on the Intellectual Property Office website.

The National Archives generally does not hold patents or specifications after 1852. However, we hold many records relating to patents which include:

You can search these records in our catalogue using keywords. Most Patent Office records have the Board of Trade (BT) department code.

You can also browse the Patent Office division in our catalogue.