UK Export Finance (UKEF), a government agency in the Department for International Trade, is spending billions of pounds on the projects, Newsnight researchers have found.

This is despite a government commitment to cut down on carbon emissions.

The Conservative Environment Network (CEN) called the figures "staggering".

The organisation, which describes itself as a forum for conservatives who support conservation and decarbonisation, said funding the projects was "a blemish on the UK government's record on climate change".

An investigation by Newsnight, in conjunction with Unearthed - Greenpeace's investigations unit - found that UKEF has helped to finance oil and gas projects that, when complete, will emit 69 million tonnes of carbon a year, according to government estimates.

That's nearly a sixth of the total annual carbon emissions of the UK.

The government calculated the UK's total emissions to be 449 million tonnes of C02e (carbon dioxide equivalent) in 2018.

It said the 69 million tonne estimate was a "worst case" scenario - and the emissions of the projects may be lower when the projects are operational.

The UK is just one of a number of backers for these projects.

UKEF was set up a century ago - and aims to support British businesses abroad.

Earlier this week, Boris Johnson announced that the UK would no longer finance coal mining or coal-fired power plants abroad.

Newsnight's investigation found all of UKEF's current fossil fuel financing was for oil and gas projects, and not coal.

Newsnight research also found that - since 2010 - UKEF has financed £6bn of fossil fuel projects. Financing has been provided to some of the biggest oil and gas companies in the world.

The projects that UKEF helps to fund abroad include oil refineries, power plants and liquefied gas extraction.

Last year, the Environmental Audit Committee (EAC) published a report criticising UKEF as an "elephant in the room undermining the UK's international climate and development targets".

Kerry McCarthy MP, a Labour member of the EAC said: "It's ludicrous that we would be funding something overseas, that we are purporting to be moving away from in our own country.

"There's just a complete disconnect, there's complete hypocrisy, that we boast of cleaning up our own act, but actually we are enabling other countries to carry on polluting."

UKEF told Newsnight: "We are committed to working with countries across the world to unlock their renewable energy potential and support their transition away from fossil fuels to cleaner alternatives."

As well as investments in fossil fuels UKEF has also financed some renewable projects.

The CEN's Sam Hall said the government needed to solve the issue of what UKEF funds before COP26 - an international climate change conference due to be held in Glasgow in November this year.