The government produces an annual analysis of climate change emissions, but the final report is not done until a year or two after the reporting year, so the latest full analysis available is for 2017 emissions. There has been some further progress in reductions particularly due to offshore wind coming onstream.
The chart shows a very simple summary of the largest emissions sectors. The numbers are from table 5 in this report that explains further: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/776085/2017_Final_emissions_statistics_-_report.pdf
The first thing to note is that this just accounts for emissions that happen in the UK, and does not count those that are accounted for overseas due to things we import – particularly meat/dairy, animal fodder and biomass (wood and palm oil etc), which have a major impact due to deforrestation, for example in South America.
Most of the UK emissions come from burning fossil fuels, either for transport (27%), electricity generation (24%), or heating in businesses and homes (17%, 14%).
UK agriculture sits at 10% in the UK, due mainly to methane from animal farming. However it has a disproportionate immediate impact on biodiversity loss due to the pressure on land use and pesticides used to get high yeilds on crop lands.