LONDON, April 15 (Reuters) - Britain will study the "options" with its allies if President Bashar al-Assad again uses chemical weapons against his people in Syria, but as yet there is nothing planned, foreign minister Boris Johnson said on Sunday.

Johnson backed Prime Minister Theresa May's decision to join the United States and France to strike chemical weapons facilities in Syria on Saturday, saying it was the right thing to do to deter the further use of chemical weapons.

"There is no proposal on the table at the moment for further attacks because so far thank heavens the Assad regime have not been so foolish as to launch another chemical weapons attack," he told the BBC's Andrew Marr show. (Reporting by Elizabeth Piper Editing by Alexander Smith)