Foreign Secretary Boris Johnson has expressed "outrage" at the "reckless provocation" of North Korea's latest missile launch.
The rebuke came after South Korea said Pyongyang fired a ballistic missile towards the sea between the Korean Peninsula and Japan.
Mr Johnson tweeted: "Outraged at reckless provocation by #NorthKorea. Strongly condemn latest illegal missile launch by #DPRK."
Japanese officials said the missile flew over the northern Japanese island of Hokkaido and landed in the Pacific Ocean. There was no damage to ships or anything else reported. Japan's NHK TV said the missile separated into three parts.
The launch comes amid heightened tension in East Asia after North Korea threatened to fire missiles towards the American territory of Guam.
The launch happened after Pyongyang expressed anger at joint US-South Korea military exercises.