The UK has backtracked on its pledge to ban slave labour from its renewable supply chain to meet Ed Miliband's Net Zero goals.

Labour enshrined in law a promise that its state-run company GB Energy would not fund companies using forced labour.

But following a probe that revealed that it had funded solar panels for schools without guarantees that they were ethically manufactured, it rowed back.

In a statement, the energy department introduced a new caveat to say that it would only ensure panels were free from forced labour 'as far as possible'.

It came as the Government announced that it would push to rid the energy system of fossil fuels and focus on renewables instead.

The move provoked fury from campaigners who demanded that ministers uphold the commitment to guaranteeing supply chains.

Sir Iain Duncan Smith, an arch China-sceptic, pointed to the Government legislation which he said had 'no caveat'.

The amendment committed ministers to taking 'measures for ensuring that slavery and human trafficking is not taking place in its business or supply chains.'

But a Government spokesman introduced a caveat, saying: 'We have strict procurement controls in place to ensure that any solar panels are free from forced labour, as far as possible.' 

Eleanor Lyons, the independent anti-slavery commissioner, said: 'The race to net zero should never come at the expense of people forced to produce goods in horrendous conditions, working endless hours and under constant surveillance.

'The Government promised taxpayers their money would not fund products linked to forced labour. They should not abandon that commitment.'

Labour's admission came after Politico exposed that GB Energy had funded firms that cannot guarantee their supply chains are free from this risk.

It reported that the company had even awarded contracts to companies that human rights experts have identified as having a high risk of exposure to forced labour.

The rush towards Net Zero leaves the UK reliant on importing solar panels from China, which dominates global supply chains.

Many of the materials come from the Xinjiang province which is home to the Uyghurs who China has been accused of using as slave labour.

GB Energy has a budget of £8billion and has funded solar panels for schools and hospitals to provide renewable energy for them.

Politico investigated one of these projects from last year and found that the companies involved could not guarantee that their supply chains were free from forced labour.

Of the seven companies involved, five did not give that guarantee, one did not respond and another obtained panels from a manufacturer which said the 'risk remains present'.

One manufacturer was even named in a 2023 report from Sheffield Hallam University as having 'very high' risk of exposure to products from Xinjiang.

Labour MP Sarah Champion, who helped to commit GB Energy to tackling forced labour risks in an amendment to legislation, said the Government should ensure this is done.

'My amendment to GBE requires companies taking government contracts to prove there is no modern slavery in their supply chains. Taxpayers deserve this reassurance,' she said.

A Government spokesman said: 'We have strict procurement controls in place to ensure that any solar panels are free from forced labour, as far as possible.

'All contracts issued under the schools and hospitals solar initiative complied with UK procurement rules, including extensive requirements under the Modern Slavery Act.'