Relatives of soldiers killed in Iraq will today ask the UK's senior judges to rule that they can bring damages claims against the Government.
Lawyers have said the families want the right to sue for negligence to make claims under human rights legislation.
The hearing, which is expected to last four days at the Supreme Court, will analyse arguments from lawyers representing relatives and counter-arguments from the Ministry of Defence (MoD).
Relatives say the MoD failed to provide armoured vehicles or equipment which could have saved lives, and should pay compensation.
But the MoD says decisions about battlefield equipment are for politicians and military commanders.
More top news
South African anti-apartheid leader Ahmed Kathrada has died at the age of 87.
Cyclone Debbie has made landfall in Australia, battering the Queensland coastline with winds of up to 163mph (263km/h) and heavy rains.
Travel vaccinations, gluten-free foods and omega-3 supplements may no longer be available on the NHS under major cost-cutting plans.