Proposed cuts to legal aid could deny justice to those who need it most, the UK's top judge has warned.
Supreme Court president Lord Neuberger said reduced access to legal aid could lead to inefficient claims costlier for the court system.
If people had to drop claims, it would be "a rank denial of justice and a blot on the rule of law", he said.
The Ministry of Justice said the annual £2bn bill for legal aid was "costing too much".
An MoJ spokesperson said that the £350m cuts "will create a sustainable legal aid system that will still be one of the most generous in the world".
"At a time when major financial challenges are being felt by businesses and households across the country the legal sector cannot be immune from the government's commitment to getting better value for every penny of taxpayers' money we spend."
Lord Neuberger's comments came as he delivered the annual Tom Sargant Memorial Lecture.
He also used the speech, organised by legal campaign group Justice, to urge ministers to be "very careful" about restricting the right of people to use a judicial review when challenging the decisions of local councils and other public authorities.
He said moves to discourage "weak" applications were "understandable, even laudable", but warned: "One must be very careful about any proposals whose aim is to cut down the right to judicial review.
"The courts have no more important function than that of protecting citizens from the abuses and excesses of the executive - central government, local government, or other public bodies."
Warning of the potential harm from government cuts to the legal aid budget, Lord Neuberger said: "Cutting the cost of legal aid deprives the very people who most need the protection of the courts of the ability to get legal advice and representation."
'Blot on law'
He said recent changes to the system had reduced the types of claim which qualified for support and increased the "stringency" of the eligibility criteria.
He added: "If a person with a potential claim cannot get legal aid, there are two possible consequences. The first is that the claim is dropped - that is a rank denial of justice and a blot on the rule of law.
"The second is that the claim is pursued, in which case it will be pursued inefficiently, and will take up much more of the court staff's time and of the judge's time in and out of court."
This would mean "greater costs" and delays for the court system, he said.