The total stands at 541 after 19 more cases were confirmed in England, as well as 13 new ones in Scotland and one further case in Northern Ireland.
Of those in England, five were in the South East, four each in London and the East, as well as cases in the Midlands, North West and Yorkshire and Humber.
It comes after a pregnant woman with swine flu gave birth prematurely.
The baby was born on Monday afternoon, at 29 weeks, in the Royal Alexandra Hospital in Paisley.
The 38-year-old mother is in a critical but stable condition, and the baby is in intensive care but stable.
The regions affected by the new Scottish cases include Fife, Forth Valley, Glasgow and Clyde and the Highlands.
Worldwide there have been 19,315 confirmed swine flu cases in 66 countries, with 117 deaths - all in Mexico and the US.