Peers will hear from a co-chair of the International Bar Association’s Human Rights Institute and former heads of the British Army, Royal Navy and the Royal Air Force when they begin the second reading of the Overseas Operations Bill at 2pm.

Human rights campaigners have called on the UK government to scrap the proposed law after failed attempts by MPs, including Conservative MP David Davis and the SNP parliamentary group, to exclude prosecutions for torture or genocide from its remit.

A YouGov poll commissioned by Amnesty International shows that a majority of people (56 per cent) are concerned about the prospect of British troops being given immunity from prosecution, with nearly a third (29 per cent) saying they are “very concerned”.

Three-quarters (75 per cent) of those polled also said they believe torture is unacceptable, while nearly two-thirds (62 per cent) agreed that granting immunity to British soldiers would make it harder for the UK to call on other countries to bring charges for war crimes committed by their armies.

Kate Allen, director of Amnesty International UK, said: “This polling clearly shows that the UK public does not believe British soldiers should be above the law or given a free pass for war crimes.

“The government has tried to sell this shockingly unprincipled law using a spurious argument about ‘vexatious’ claims that would amount to granting defacto immunity for acts of torture and other serious crimes after five years.

“The UK’s international reputation is at stake - this would make terrible law and set a terrible example.

“The House of Lords should oppose this shameful bill and ensure that British troops are not granted a licence to torture.”