The threat of coronavirus becoming a pandemic is now “very real”, ​the World Health Organisation has warned.

The UN health agency’s director general suggested the virus gaining “a foothold in so many countries” meant the risk of a pandemic had increased.

But, Dr Tedros Adhanom Ghebreyesus said it would be the first pandemic in history that could be controlled, adding: “The bottom line is: we are not at the mercy of this virus.”

He urged governments dealing with outbreaks to focus on both containment and mitigation to stop the spread of the virus.

The warning came hours after Boris Johnson and health minister Matt Hancock insisted the UK – now home to 319 confirmed cases – is still in the “containment” phase, the first of three in Whitehall’s action plan of contain, delay and mitigate.

Moving to the delay stage would likely see the introduction of “social distancing” measures – such as banning large events, closing schools and encouraging people to work from home, which were mulled by minister’s at a Cobra meeting chaired by Boris Johnson on Monday.

Announcing the fourth death in the UK – a Wolverhampton patient in their 70s with underlying health problems – Mr Hancock told MPs of his plans for the outbreak.

“We continue to work to contain the virus, but we’re also taking action to delay its impact, to fund research and to mitigate its consequences,” Mr Hancock said in the Commons.

England’s chief medical officer Chris Whitty insisted there would be overlap between the three phases, but warned “there is a risk if we go [to the next phase] too early people will understandably get fatigued and it will be difficult to sustain this over time”.

While he lamented the widespread nature of the outbreak, Dr Tedros suggested the international community should take heart from the fact that only a handful of countries are showing signs of sustained community transmission – with most still having defined clusters or confined cases.

“As long as that’s the case, those countries have the opportunity to break the chains of Covid-19 transmission, prevent community transmission and reduce the burden on their health systems,” he said.

He welcomed news that major outbreaks were showing signs of being brought under control in South Korea and China, and also lauded Italy’s “aggressive” efforts to contain its outbreak – where the death toll skyrocketed from 366 to 463 on Monday.

Italy has introduced the most dramatic measures of any European nation so far, effectively quarantining more than 16 million people as it placed Lombardy, home to Milan, and 14 other regions on lockdown.

People within those regions must receive special permission to travel, while schools, gyms, museums, nightclubs and other venues across the whole country have been closed.

Despite the number of new cases in Italy soaring from 7,375 to 9,172 on Monday, Dr Tedros said successes in China and South Korea demonstrated it’s “never too late to turn back the tide on this coronavirus”.