Labour MPs have voted to block a ban on the Government buying solar panels where there is “credible evidence” of modern slavery in the supply process.

Peers concerned that China has used forced labour to make the panels had amended legislation in an attempt to stop GB Energy, Britain’s new publicly owned energy company, buying such products.

But ministers whipped Labour MPs to vote against the proposed amendment, which could mean that solar panels made by slaves end up being installed on public buildings.

Many solar panels bought under the Government’s plans to reach net zero electricity by 2030 will come from China, which manufactures around 80 per cent of global supply.

The Xinjiang region, where there are widespread suspected human rights abuses against the Uyghur population, produces up to 40 per cent of polysilicon, a vital component for the panels.