The Republican presumptive presidential nominee Donald Trump has edged ahead of Democrat frontrunner Hillary Clinton in the polls.

The GOP candidate has come close to leading Clinton in the polls on two previous occasions but this is the first time Trump has moved ahead of Clinton in an average head-to-head poll.

Last month, Trump polled ahead of Clinton only if the option not to vote was removed, whereas recent data from RealClearPolitics (RCP) puts Trump 0.2 points ahead of Clinton in a straight average of the polls.

RealClearPolitics (RCP), which takes an average of data from different nationwide polls, puts Trump at 43.4% while Clinton is on 43.2%.

Of the five polls RCP looks at, Trump is ahead in three, with leads of five, three and two points over Clinton in Rasmussen Reports, Fox News and ABC News/Washington Post respectively. The two polls that put Clinton ahead of Trump show the Democrat hopeful three ahead in the NBC News/Wall Street Journal poll and six ahead in the CBS News/NY Times poll.

Although Clinton has not yet won the Democrat nomination, she is widely expected to do so, having built up a significant lead on rival Bernie Sanders. But having previously polled very well against Trump, the Republican has been gaining ground, polling particularly on national security and the economy.

Voters also seem to respond well to Trump's 'tough on terrorism' rhetoric, with research from the Economist Intelligence Unit suggesting Trump would be more likely to reach the White House if there were a terror threat in the US.