A vaccine for coronavirus Covid-19 is likely to take up to a year to develop, the government's research chief has said.

Sir Mark Walport, the chief executive of UK Research and Innovation and a former chief scientific advisor said it was "unlikely that we're going to have a vaccine for the present round of this epidemic".

His comments follow reports that "encouraging" research at Imperial College London means a vaccine could being testing on humans in a few months' time.

"Vaccines are being developed at a very fast rate and so there are a number of candidates: big companies, small companies, universities, all working," Sir Mark explained in an interview on Sky News.

"The challenge here is to make sure that the vaccine is safe and that it works and that unfortunately that takes period of time to do.

"So realistically it's very unlikely that we're going to have a vaccine for the present round of this epidemic. We're talking months: up to a year."

The former chief scientific advisor is leading the UK government's coordinated research effort to develop a vaccine for the disease.

A number of researchers across the globe are working to develop such a treatment. The Covid-19 has infected more than 150,000 people around the world so far, with numbers expected to climb.

Scientists in the US have already launched an appeal for volunteers to take part in the trials, offering a cash incentive.

But the Observer newspaper reports concerns from scientists that the UK's decision to leave the European Medicines Agency as part of Brexit will likely mean Britain gets any vaccine slower than EU countries.

Addressing the issue of how many people would ultimately be infected, Sir Mark said: "Over time it's quite likely that large percentage of populations around the world will get it: most of them very mildly indeed and many of them sub-clinically.

He also endorsed the way the government had approached the pandemic, stating that "the UK has the most deeply-embedded system of scientific advice in emergencies I think of any country in the world". He added that it was "absolutely right" to publish the data on which the modelling of the response had been based.