According to Hubert Lamb, the summer of 1826 may have been hotter in England than 1976.
08 Jul 1826, 2 – The Leeds Mercury at Newspapers.com
29 Jul 1826, 2 – The Leeds Mercury at Newspapers.com
08 Jul 1826, 4 – The Yorkshire Herald and the York Herald at Newspapers.com
https://www.metoffice.gov.uk/hadobs/hadcet/ssn_HadCET_mean.txt