Taken from this post, which has the National Food Strategy report as the source. See figure 9.3 on page 90.

About 70% is devoted to agriculture, mainly livestock and livestock feed and pasture.

The right-hand side of the chart, using the same scale, shows how much land is used overseas to produce food for the UK. About half of the total land use takes place overseas.

The combined land area for rearing beef and lamb for UK consumption is larger than the UK itself.