Using data from 7 d weighed dietary records, dietary intake and sources of phylloquinone (vitamin K1) were examined by socio-demographic and lifestyle factors in 1916 participants aged 16-64 years from the 1986-7 Dietary and Nutritional Survey of British Adults, and 1423 participants aged 19-64 years from the 2000-1 National Diet and Nutrition Survey. Using UK-specific food content data, geometric mean phylloquinone intakes were estimated as 72 (95% CI 70, 74) and 67 (95% CI 65, 69) microg/d in 1986-7 and 2000-1 respectively (P<0.001). In 1986-7, 47% of participants had phylloquinone intakes below the UK guideline for adequacy (> or =1 microg/kg body weight per d), compared with 59% in 2000-1 (P<0.001). In both surveys, daily phylloquinone intake was higher among men than women and increased significantly with age. Participants of manual occupational social class, or who were smokers, had lower phylloquinone intake than their counterparts. Participants living in Scotland and northern England had lower phylloquinone intake than those living elsewhere in mainland Britain, particularly in 1986-7 when the contribution from vegetables was also lower than elsewhere. However, by 2000-1 this regional difference was no longer significant. Overall, vegetables contributed 63% of phylloquinone intake in 1986-7 and 60% in 2000-1, with cooked leafy green vegetables (LGV) providing 23 and 19% respectively. In both surveys, the contribution of vegetables (cooked LGV in particular) was directly associated with age. These data show a decrease in phylloquinone intake from 1986-7 to 2000-1, mainly owing to lower consumption of cooked LGV.