Hillary Clinton (above) would be the frontrunner if she jumped into the Democratic race for president, according to a new Harris Poll

Hillary Clinton would be leading the race for the Democratic nomination for president if she declared her candidacy, according to a new poll.

The online survey by Harris Poll which was released by Harvard University’s Center for American Political Studies shows the former secretary of state in first place with 21 per cent of the vote.

Joe Biden, the current frontrunner, would receive 20 per cent while Senator Bernie Sanders is at 12 per cent.

Senator Elizabeth Warren comes in fourth at 9 per cent followed by former New York City Mayor Michael Bloomberg, who is at 7 per cent.

The poll, which surveyed 1,859 voters, was taken between November 27 and 29.

If Clinton stayed out of the race, Biden maintains his advantage with 29 per cent followed by Sanders, who gets 15 per cent. Warren comes in third at 13 per cent.

Last week, Clinton refused to completely rule out a late entry into the field of candidates.

During media appearances in the United Kingdom last month, Clinton twice hinted that she could still make a late entry into the field.

Speaking on the BBC's Graham Norton Show in London on November 29, Clinton said she would 'have to make up my mind really quickly', if she was going to join the race.

Earlier last month when the former first lady and her daughter Chelsea were promoting their work, The Book Of Gutsy Women, she appeared on BBC Radio Five Live.

The survey shows Clinton with a slight edge over former Vice President Joe Biden (left). Senator Bernie Sanders (right) is in third place, according to the survey

Senator Elizabeth Warren (above), whose campaign has been struggling lately in the polls, would run in fourth place if Clinton entered the race, according to the Harris Poll survey

When asked if she would make a run for the White House for a third time, she replied: 'As I say, never, never, never say never.'

In her interview with Norton, Clinton was again asked if she would rule out joining the already 18-strong field of Democrat hopefuls.

She conceded she is going to have to make up her mind 'really quickly' about whether or not to jump into the presidential race.

Clinton has already missed the filing deadline for the first primary in New Hampshire but there is no deadline for the next caucuses in Iowa in early February.

Responding to Norton, Clinton said she had been 'deluged' over the last few weeks thinking about running again, but added that, 'right now, I'm not, at all, planning that'.

Norton asked: 'The rumor mill is flying that you could step back into the ring.'

Clinton replied: 'I hear that. I have been deluged the last few weeks with thinking about doing that, but right now I'm not at all planning that.

Hillary Clinton and her daughter Chelsea on the Graham Norton Show at the BBC in London. The episode was taped on November 10 but aired on November 29. The former First Lady refused to completely rule out a late run for the White House

'I would have to make up my mind really quickly, because it's moving very fast. But I do want to continue to influence the debate.'

In reference to her old rival Donald Trump, who defeated her in the 2016 presidential election, Clinton said she still wanted to influence the political debate even if she stayed on the sidelines in 2020.

She added: 'I'm not leaving the political arena completely, I'm working really hard to make it clear that we have to hold our current leadership accountable.

'I'm out there all the time pointing out the foolishness and craziness that we are currently experiencing.

'So I'm not going anywhere, I just don't know what role I will actually be in.'

The question of her potential candidacy came up when Clinton was asked about one of the subjects in her book, USA soccer star Abby Wambach, who retired with the tagline 'Forget Me', in order to leave the public stage and have someone else take her place.

Norton asked: 'Are you saying ''Forget me'' now?', to which Clinton answered, 'not yet', to applause and cheers from the studio audience.

She was also asked by the host if she was optimistic about the future of politics and replied: 'I am fundamentally optimistic, there's all these indicators of people trying to push the clock back on the progress we've made.

'So that does worry me but I hope that when it's all worked out people will say ''there's things we need to be smarter about, do better about''.'