A prominent climate change sceptic’s company has donated £25,000 each to both Boris Johnson and Jeremy Hunt’s leadership campaigns, openDemocracy has discovered.

Johnson and Hunt are widely seen as favourites to emerge as the final two contenders once Tory MPs begin voting on a successor to Theresa May on Thursday. Both candidates have declared over £100,000 in donations in recent weeks.

Foreign Secretary Jeremy Hunt’s largest donation was £25,000 on May 22 from First Corporate Shipping, according to the register of MPs’ interests. First Corporate Shipping is the trading name of Bristol Port, which is co-owned by Tory donors Terence Mordaunt and Sir David Ord.

Mordaunt is a director of the Global Warming Policy Forum, the advocacy arm of the climate sceptic Global Warming Policy Foundation. The group has been accused of “giving a platform to fringe climate science deniers” and getting “credibility within the political world through its high-profile Westminster connections.”

Boris Johnson also received £25,000 from the Bristol Port owners ‘“at the same time” as Hunt, Mordaunt told openDemocracy. The Tory front-runner, who launched his leadership bid today, has yet to record the donation on his register of interests. He has until later this month to do so.

Leading environmental campaigners from Greenpeace UK criticised Johnson and Hunt for being “bankrolled by a director of Britain’s leading climate denial group.”

Green Party co-leader Sian Berry said that the fact that Hunt had declared the donation and Johnson had not yet done so also “raises the question about who else is funding Boris Johnson that we don’t know about.”

Tory climate change denial

The Global Warming Policy Foundation was set up by former Tory chancellor Nigel Lawson, based at 55 Tufton Street, the same address as a number of think tanks who do not declare their funders. In 2014, the lobbying group the Global Warming Policy Forum was spun out, after the Charity Commission ruled that the foundation had breached rules on impartiality.

Mordaunt told openDemocracy that the forum was not involved in climate change “denial” but that “our knowledge of global warming is very imperfect and that if it is happening, it is happening far slower than most experts and climate models have predicted.”

The United Nations describes climate change as “the defining issue of our time”. But a number of Tory leadership hopefuls have previously questioned global warming.

Boris Johnson has described to concerns about climate change as a “primitive fear” that is “without foundation.” As health secretary Jeremy Hunt said that the "ageing population" poses a challenge "as serious as global warming"

Michael Gove, another prominent Tory leadership candidate, has praised reports published by the Global Warming Policy Foundation. As education secretary, a spokesperson for Gove dismissed climate science as “a particular political or ideological point of view” in opposition to teaching the subject in school.