UK Foreign Secretary Boris Johnson is in trouble after sending a congratulatory message to President Uhuru Kenyatta after the Supreme Court on Monday upheld his victory in the October 26 elections.

Johnson is under increased pressure and growing criticism for "reacting too early" in congratulating Kenyatta after he appeared to become the first senior foreign official to endorse the Kenyan President.

“We welcome Kenya’s supreme court decision upholding  Kenya’s 26 October presidential elections,” a spokeswoman from the UK Foreign Office said. “We look forward to working with the new Kenyan government.”

UK's The Telegraph said the Foreign Secretary handed the Kenyan government a diplomatic coup after he broke ranks with his western counterparts by offering Mr Kenyatta his congratulations in a telephone call on Monday, according to officials in Nairobi.

The leading publication stated that Johnson’s gesture left Britain isolated, with other Western missions in Nairobi saying they had chosen to delay offering their congratulations in stands against aspects of Mr Kenyatta’s campaign and the deadly suppression of protests in recent months.

According to them, apart from Britain, the only other countries known to have congratulated Mr Kenyatta are South Sudan, Uganda and Bangladesh.

It is reported that Mr Johnson had a conversation with Kenyan Foreign Affairs Cabinet Secretary Amb. Amina Mohammed, only hours after the country’s supreme court upheld Mr Kenyatta’s victory in a rerun election held last month.

NASA have condemned the Foreign Secretary’s intervention, accusing him of placing “British interests” above “British values” by propping up “an illegitimate regime”.

“We feel that such a congratulatory message in light of everything that has happened does not help in achieving or reinforcing democracy on the continent,” NASA stated.