In England and Wales legal aid is available for the following types of cases:
Legal aid is subject to a means assessment, so a person's income and savings or other capital will be taken into account to establish if they are eligible for this.
Some cases are also subject to a merits assessment, for example, an appeal against a refusal of asylum. When the merits test applies, the legal representative will need to assess the likelihood of the case succeeding and can only continue to provide representation if the case has 50% or more chance of success.
See the Law Society information about help with paying for legal costs.