The U.K. is making "extensive preparations" to begin the next phase of its response to the COVID-19 outbreak, Prime Minister Boris Johnson announced on Monday.

"Our action plan as you know sets out four phases of our approach to tackling the virus; Contain, Delay, Research and Mitigate. We remain in the Contain phase of the outbreak but watching what is happening around the world, our scientists think containment is extremely unlikely to work on its own and that is why we are making extensive preparations for a move to the delay phase," PM Boris said in a press conference alongside Chief medical Office Chris Whitty and Chief Scientific Adviser Patrick Vallance.

 "The more we can delay the peak of the spread to the summer, the better the NHS will be able to manage," he added.

Boris' announcement comes as the World Health Organization (WHO) reported that COVID-19 cases had surpassed100,000 spanning across 100 countries.

"It's certainly troubling that so many people & countries have been affected, so quickly," WHO Director-General Tedros Adhanom said in a briefing on Monday.

"The great advantage we have is that the decisions we all make – as governments, businesses, communities, families & individuals – can influence the trajectory of this #COVID19 epidemic," he added.