Watch as US states hold presidential primary elections and caucuses on Super Tuesday (5 March).

       The biggest day of the US primary season promises to have a decisive impact on both the Republican and Democratic races.

       As it stands, Donald Trump looks all but certain to be the GOP’s presidential candidate once again in 2024, having already chalked up big wins in the Iowa caucus and the New Hampshire, Nevada, South Carolina, Michigan, Idaho and Missouri primaries.

       Only one of his challengers - Nikki Haley - remains in the race.

       The former South Carolina governor picked up a much-needed win in Washington DC’s primary on Sunday, her first of the season, beating Mr Trump by 62.3 per cent of the vote to his 33.3 per cent, scooping up 19 delegates in the process.

       Meanwhile, the Democratic contest is even more one-sided, with Joe Biden seemingly nailed-on to be his party’s candidate again as he seeks a second term in the White House.