Eight Conservatives will fight it out to succeed Boris Johnson as party leader and British prime minister after winning enough nominations from their colleagues to go through to the first round of voting on Wednesday.

Only two hopefuls failed to secure the 20 necessary nominations, leaving a wide field of candidates seeking to win the backing of the party with promises of tax cuts, honesty and serious government - a contrast to Johnson who was forced to announce he would resign after a series of scandals.

Former finance minister Rishi Sunak (above) is the bookmakers' favourite, and among those he will be taking on are his successor Nadhim Zahawi and foreign minister Liz Truss in what is becoming an increasingly bitter and divisive contest.

The next British leader faces a daunting in-tray while support for the Conservatives is also falling, polls show.

Britain's economy is facing rocketing inflation, high debt, and low growth as people grapple with the tightest squeeze on their finances in decades. All of this is set against a backdrop of an energy crunch exacerbated by the war in Ukraine which has sent fuel prices soaring.

As the contest intensifies, rival campaigns stepped up private criticism of each other and pointed to either financial or other questions hanging over their opponents.

Sunak kicked off his campaign by portraying himself as the serious candidate, promising "grown-up" honesty "not fairy tales", seeking to contrast himself with the extensive tax cuts pledged by most of the other candidates.

"It is not credible to promise lots more spending and lower taxes," Sunak said, saying tax cuts could only come after soaring inflation was tackled.

As finance minister, Sunak set Britain on course to have its biggest tax burden since the 1950s after he oversaw a huge rise in government spending during the coronavirus pandemic, and most of the other hopefuls have turned their fire on him by saying they would oversee cuts immediately.

'Dirty tricks'

Sunak has the widest support among colleagues who have publicly expressed their views.

Penny Mordaunt, a junior trade minister who is also heavily tipped, topped a poll of Conservative party members and she too has tried to strike a more measured tone on tax, saying that now is not the time to cut government spending.

"The others will obviously try to secure votes, they will try to put up flares for particular caucuses," she told LBC radio. "This is not the time to be making radical tax policies and promises."

Attorney General Suella Braverman; the former health and foreign minister Jeremy Hunt; Tom Tugendhat, chair of Parliament's foreign affairs committee; and Kemi Badenoch, a former junior minister who is scooping up support on the right wing of the party, are the other candidates to enter the first round of the contest.

Transport Secretary Grant Shapps earlier became the first candidate to end his bid, throwing his support behind Sunak, while Home Secretary (interior minister) Priti Patel announced she would not be standing.

Foreign Secretary Truss received the backing of two ministers closest to Johnson - Nadine Dorries and Jacob Rees-Mogg - who have both been critical of Sunak.

Dorries accused Sunak of using "dirty tricks" to manipulate the leadership contest, with votes being loaned to Hunt's campaign because they view him as easier to beat.

Sunak's team did not respond to a request for comment.

The 1922 Committee of Conservative Members of Parliament, which is organising the contest, says the field will soon be whittled down with repeated votes in the next few weeks, with the final two then selected by the fewer than 200,000 party members by July 21.

The winner, and Britain's new prime minister, will be announced on Sept 5.

Meanwhile, the opposition Labour Party said the government was "running scared" after it blocked an attempt to call a confidence vote in Johnson on Wednesday to force him from office immediately.

The government said Labour was trying to "play politics" and it would allow Labour to call a confidence vote if the wording of the motion was changed to remove reference to Johnson.

- Reuters