"The (British) Prime Minister spoke to Prime Minister (Narendra) Modi this morning, to express his regret that he will be unable to visit India later this month as planned," a spokesperson for Downing Street told the media.

Last night, the British government announced a complete lockdown to contain the spread of coronavirus before mass vaccinations turned the tide.

"In light of the lockdown announced last night, and the speed at which the new coronavirus variant is spreading, the Prime Minister said that it was important for him to remain in the UK so he can focus on the domestic response to the virus," the spokesperson added.

Also read: Global COVID caseload crosses 85.6 million

Confirming the phone conversation between the Indian PM and Johnson, sources told UNB that top diplomats at the External Affairs Ministry "now face a herculean task to find another head of state or government to grace the Republic Day parade as the chief guest".

Johnson had accepted India's invitation to attend the parade last month.

"I am absolutely delighted to be visiting India next year at the start of an exciting year for Global Britain, and look forward to delivering the quantum leap in our bilateral relationship that Prime Minister Modi and I have pledged to achieve," he had said in a statement.

"The British PM will use his visit to India to boost cooperation in areas that matter to the UK and that will be priorities for our international engagement throughout 2021 -- from trade and investment, to defence and security, and health and climate change," his office had said.

Also Read: UK ramps up inoculations with Oxford-AstraZeneca vaccine

Johnson would have been the second British leader to attend the Republic Day parade in Delhi as the chief guest after John Major in 1993.

India honours January 26 every year, the day on which the country's Constitution came into effect in 1950, replacing the Government of India Act (1935) as the governing document and thus, turning the nation into a newly formed republic.

However, this year, India has decided to scale down the Republic Day parade in the wake of Covid. The distance of the parade has been cut down to half -- from 8.2km to 3.3km. The spectator strength has also been brought down to 25,000 from 1,15,000.

Also Read:  India tests vaccine delivery system with nationwide trial