PRIME Minister Boris Johnson says that a coronavirus vaccine has cleared a "significant hurdle", but there are many more to come.

This follows news that the first Covid-19 vaccine, announced by German pharmaceutical company Pfizer, could offer 90 per-cent protection from the virus.

In his Downing Street press conference this evening, Monday, the PM said that the UK will be ready when the vaccine is approved.

But he also warned that the biggest mistake would be to "slacken our resolve at a critical moment".

He said: “People are asking does the progress towards a vaccine mean we are at the beginning of the end?

“The Pfizer vaccine has been tested on over 40,00 volunteers, and has proven to be 90 per cent effective, but the findings need to be peer reviewed.

“We have cleared one hurdle, but there are several more are to go. If and when it is approved, we will be ready to use it.

“We have ordered enough doses for one third of the population and ordered over 300 million doses from other candidates.

“These are very, very early days. We absolutely cannot rely on this news as a solution, and the biggest mistake would be to slacken our resolve at a critical moment.”

Mr Johnson added that there is "no substitute" for national restrictions and good hygiene, and that it is "more important than ever" to follow lockdown rules.

This view was echoed by deputy chief medical officer Professor Jonathan Van-Tam, who claimed that the vaccine news is a "very important scientific breakthrough".

He said: “Today’s news is the first step and it is very exciting, but the message is stand fast and do not get too over excited.

“Results show the effectiveness of this first vaccine. The next step is to see the safety data in the next few days. Safety is more important than vaccine effectiveness.

“I’m hopeful but not yet certain that some vaccines could be seen by Christmas.

“The vaccine announced today is good news for other vaccines to come. It is like getting to penalties in the cup final and the first player scores. The cup is not won yet, but it tells you that goalkeeper can be beaten.”

Prof Van-Tam added: “This may be a swallow, but it is not the summer.

“It would be a colossal mistake to relax at this point.”